A neurophysiological assay was conducted to investigate the effects of five mixtures of cypermethrin stereoisomers on firing of the sensory nerve in the isolated mesathoracic leg of susceptible and resistant houseflies. Each mixture induced an elevation of the firing frequency, then gradual drop and eventually to blockade. Nerve sensitivity was calculated by the blocking time and cyermethrindoses. The sensitivity of the susceptible strain toward five mixtures of cypermethtin stereoisomers was in the order C₄＞ C₁＞C₂＞C₃＞C₅. The sensitivity was dependent on the ratio of trans- to cis-isomer in the mixtures, the higher the ratio,the higher the sensitivity. The results showed that the nerve sensitivity of resistant houseflies decreased markedly. It is suggested that the decrease of nerve sensitivity might be the most important mechanism of resistance in the houseflies to cypermethrin. The resistance levels of RC₁ was the highest among the resistant housefly strains, but its neurosensitivity was also the highest. It was inferred that the main resistance mechanism of RC₁ to cypermethrin is different from that of other strains.

The mechanism of resistance to fenitrothion in the rice stem borerChilo suppressalit Walker is comprehensively investigated. Resistant strain ?, initiated from a field population, was selected successively by fenitrothion to the 7th generation and the resistant ratio was 14.1 as compared with that of the susceptible strain (S), which was obtained by selection with single-egg mass method. Synergism experiments showed that the synergistic ratio of DEF and PBO to fenitrothion in R strain were 1.3X and 34.8X, respectively. It suggested that resistance to fenitrothion was partially associated with multiple function oxidase (MFO). Furthermore, the activities of non-specific esterase, carboxylesterase (CarE) and MFO were determined in vitro. The results indicated that the activities of non-specific esterase in R and S strains showed no significant difference when using substrates of a-naphthyl acetate and β-naphthyl acetate. But there was difference in the activity to Care between R and S strains. The activities of Care from the larvae of R strainwith above-mentioned substrates (with 10^-4 esterin) were 2.42-and 2.92-fold higher than that of S strain, respectively. The ratio of 0-demethylation activities of MFO extracts from R strain to that of S strain was found to be 1.43. The acetylcholinesterase (ACHE) activities and the kinetic parameter, K_m and I₅₀ of paraoxon were also measured. The ratios of activities, K_m and I₅₀ of R strain to that of S strain were 1.6, 1.7 and 2.0, respectively. It was apparent that the Ache in R strain have altered. From the results obtained, it is concluded that the onset of resistance to fenitrothion in the rice stem borer is due to multi-factor including high activities ofCarE, MFO, enhanced O-demethylation of MFO and insensitivities of ACHE.

Based on the in vitro effect on protease activity of larval midgut,soybean trypsin inhibitor (STI) was suggested as the potential resistant agent to cotton bollworm, Helicoverpa armigera. It was incorporated in the larval artificialdiet at 0.84-4.2% (dry weight) to determine its acute and chronic effects on the growth and in vivo midgut protease activity of cotton bollworm. Ingestion of 4.2% STI in short term resulted in reduced larval growth rate, increased low alkaline trypsin-like enzyme activity, decreased high alkaline trypsin-like enzyme activity,decreased chymotrypsin-like enzyme activity, and decreased total proteolysis. When the larvae chronically ingested 0.84% STI, low alkaline trypsin-like and chymotrypsin-like enzyme activities were significantly elevated, high alkaline trypsin-like enzyme activity was markedly declined, and total proteolysis had no significant change. When the larvae chronically ingested 4.2% STI, high alkaline trypsin like enzyme activity and total proteolysis were significantly decreased, but there was nosignificant elevation of low alkaline trypsin like and chymotrypsin-like enzyme activities. Retarding effect of STI on growth of the larvae was significant but not proportional to the dosage of STI. Thus, the mechanism of anti-nutritional action of proteinase inhibitor seems to be complicated, and pernicious hyperproduction ofsome protease may be only one aspect of the action. Influence of cooperative prote ases activity may still be the basis in mode of action.

The stylet penetration and suck behaviour of soybean aphid, Aphis glycines Mat., on host and non-host plants was monitored by using an electrically recording method (EPG). The results showe4 that phloem ingestion was reduced or did not happen on the non-host plants, Gossypium hirsutum, Cucumis sativa andLuria cylindrica, when compared with that on the host plant, Glycines max. The non-host plants possess resistance against A. glycines. And with the difference of the non host plants, the factors affecting ingestion and their position on the plant were different.

The flight capacity of female adult in relation to oviposition in Oriental armyworm, Mythirnna separata (Walker), one of the most detrimental migratory insect pests in China, was determined by the tethered-flight technique under laboratory condition. The females were more capable of flight as their age increased in daysand reached a peak on the days immediately after ovipositon began, with an average of 10.1 hours in duration and 58.6 kilometers in distance during the 12-hour test,indicating that there is perhaps no oogenesis-flight syndrome in this species. The flight capacity of the female, however was significantly declined 2 days after oviposition (DAO) and almost ceased on 6 DAO. The flight capacity of female was also highly related to the number of egg they laid. About 55% of the moths flow, over 36 kilometers when they laid less than 300 eggs while none of them could fly such distance when they laid more than 1200 eggs. It is therefore deduced that the incidence of migration is just at the post-teneral stage of the adult in M. seperatcr since the female's flight capacity was sharply declined as the ovipositional period extended and egg number increased. The flight capacity remained in the ovipositing female is of great significances in food and ovipositional site finding for its weeklyovipositional period both in the laboratory and in the field.

The relationship between utilization of protein and lipid and sustainedflight in the moths of Oriental armyworm. Mythimna separata (Walker) was determined in the laboratory conditions. Under six testing regimes of tethered flight (0, 6, 12, 24, 36 and 48 hours), the body weight and lipid content in the moths declined significantly as the duration of flight extended while the content of protein was insignificantly affected. The tendency of body weight loss was consis- tent with the reduction of lipid content, and lipid consisted of 60% of the body weight reduction. It seemed that the rate of lipid reduction was more steady as the flight period extended. The amount of lipid utilized during flight in females was 8.9-23.6 mg/h (actual flight) and 1.7-4.0 mg/km, while that in males was 7.2-11.8 mg/h and 1.4-2.2 mg/km according to our calculation. Based on the results obtained, it was concluded that the lipid is the major energy source for sustained flight in the moth of M. separata.

In this paper, the method of insect population dynamic simulation has been improved, which integrates some advantages of population models that have been published. Based on the population simulation model of paddy stem borer Tryporyza incertulas (Walker) (PSB) and yield loss rate forecasting model of rice crop,she optimal management decision problem of PSB population was studied with theaim to obtain maximal net revenue. The net revenue was influenced by several control strategies and their combinations such as adjusting the time of seedling transplantation, using resistant rice varieties, protecting and utilizing natural enemiesand application of insecticides. The system model can provide on optimal decision strategy to effectively control PSB population, which contains measures of agricultural control, biological control and chemical control.

The present paper deals with egg diapause of Oligonychus ununguis(Jacobi). The effects of factors influencing diapause incidence including light, temperature and nutrition were investigated, and the condition terminating diapausewas recorded. O. ununguis overwinters with diapause eggs on host plant branches.Most eggs are laid in the beginning and middle of August. The threshold of photoperiod inducing diapause is at 13 hours light per day. The larva, protonymph are sensitive to photoperiodic changes, but adults and eggs are not. Lower temperature (20℃) promotes the incidence of diapause, when they are subject under the photoperiod of 10 or 13 hours per day. Similarly, diapause is also promoted by mite population density and unfavourable nutrition. The dlapause was terminated after treatment at 0℃ for 120 clays or at 5℃ or 10℃ for 100 days.

The karyotypes and C-banding patterns of Patanga japonica Boliver and P. succincta Johansson were investigated. The result showed that the chromosome number of both species are 2n(♂)= 22+X。= 23, and they are all terminal chromosomes. The karyotype formulae are 2n(♂)=2X=23t and NF=23. The total absolute length of Patanga japonica (79.75±2.22)μm exceeds that of P. Succincra (71.47±0.63)μm; and the total amount of heterochromatin of Patanga japonica (35.65%) is more abundant than that of P. succincta (18.70%). The Patanga daponica's karyotype belongs to "IB', and the Patanga succincta's belongs to "Lc".

This paper reports the results of a study on the sugar cane weevilTrochorhopalus humeralis Chevrolat, the most destructive soil-inhabiting pest of the sugarcane stumps in Yunnan. The study was conducted mainly in Luxi County, Yunnan Province, during 1989-1991. Data obtained from both laboratory observations and field survey show that the weevil passes one generation a year and overwinters in adult stage in the host stumps. The biological characteristics and behaviour of the different stages are described. Recommended control measures are mainly agrotechnical practices such as crop rotation between sugarcane and rice, keeping off two-year old rhizome of ratoon which should be ploughed out and burnedup in early spring (before mid March), etc. Applying insecticidal granules such as 3% Isofenphos-methyl or 5% Temik into the planting ditch near the host roots is also effective.

The cantharidin of Meloidae has long been used medicinally forits irritant properities, both in China and in western countries. In China its mediccinal usage may trace far back as 1-2 B. C. in "Shen Nong Materia Medica". In a book on Chinese herbal medicine, "Compendium of Materia Medica" (1596), written by the famous pharmaceutist, Li Shi-zhen of Ming Dynasty, about four hundred years ago, the author described four different kinds of meloid-beetles; by textual research we regard that they are referred to four different genera, namely:Epicaura Redt. (葛上亭长), Lytta Fabr. (芜菁), Mylabris Fabr. (斑蟊) and Meloe L. (地胆). He had also given the usage and efficiency of the drugs both for external application and oral administration. In the "Pharmacopoeia of the People's Republ ic of China" (1985), there are listed 10 different kinds of medicinal insects and their products, of which 2 species of Meloidae are included. In China, in recent years, the clinical practice of cantharidin and its derivatives proved that they have better curative effect on primary liver cancer and also on leucocytopenia, chronicliver disease, neurodermatitis etc. In order to conserve and also effect better usage of the natural resources of Meloidae, the authors have carried out an extensive survey of Meloidae from 1989 to 1991 in the following provinces, namely Hebei (including the outskirt of Beijing), Nei Mongol (Inner Mongolia) and Xinjiang in the north and Sichuan, Guangxi, Yunnan in the south. In three years, we ascertain that among the 35 common species of Meloidae in the afore mentioned provinces, there are 19 predominant species, namely Epicauta chinensis Laporte, E. Aptera Kaszab,E. tibialis Waterhouse, E. gorhami Marseul, E. hirticornis HaagRutengerg, E. kwangsiensis Tan, E. sibirica Pallas, E. dubia Fabricius, E. rufieeps llliger, E. megalocephala Gebler, Lytta caraganae Pallas, Mylabris calida (Pallas), M. Speciosa(Pallas), M. cichorii (Linnaeus), M. frolovi (Germar), M. Axillaris Billberg, M.Phalerata (Pallas), M. sibiriea Fischer and M. mongolica (Dokhtouroff). In order to determine the quantitative levels of cantharidin contained in the above species,chemical analysis of the dried bodies of adults were carried out by thin layer chromatography and gas chromatography methods (Tables 1 & 3). The results show that about 80% of the species containing cantharidin exceed 0.35%. The "Pharmacopoeia of the People's Replubic of China" stipulates that the blister beetles with no less than 0.35% of cantharidin can be used as medicine. So the present investigation greaty increased the number of meloid species to be used as medicine. The results also show that the cantharidin levels varies among different species and also among individuals of the same species collected from different localities. To this problem further investigation is needed. As a comparison, chemical analyses were also carried out on the dry bodies of Trichodes sinae Chevrolat and Huechys sanguinea (De Geer), the results show that both contain no cantharidin.

Four species have been reported in the genus Austrohancockia Gilnther,1938, This paper reports a new one of the genus from S. China.

This paper deals with Miridae of Alashan League of Inner Mongolia.Among them a species is described as new to science, two species are recorded for the first time in China. The type specimens are deposited in the Department of Biology, Teacher's University of Inner Mongolia.

The present paper deals with the genus Nevskylla Ossiannilsson, 1954 from China. Ntvskeylla tuberculata is new to science. The type specimen are deposited in the Institute of Zoology, Academia Sinica.

This paper reports 6 new species and 1 new record of the genus Othiur:Stephens from China. Key to the known species is given. All type specimens are deposited in the Department of Biology, Sichuan Teachers College.

In this paper, the descriptions and figures of the larvae of 8 species of darkling beetles from north-western China (Ningxia, Gansu, Nei Mongol and Xinjiang), belonging to the subfamily Pimeliinae (Tenebr., Col.) are given. They are Pterocoma hedini Schust., P. loezyi Friv., Trigonoscelis sublaevigata Reitt., Sternotrigon setosa sctosa (Bates), Sternoplax (Sternoplax) szechenyi Friv., Platyope mongolica Fala., Mantichorula grandis Semenow and M. semenowi Reitt. An identification table to above mentioned species and genera of Pimeliini and Platyopini are presented. The larval specimens are deposited in Ningxia Agricultural College.

This paper describes the eggs of fourteen species of Noctuidae. Theinformation for each species includes the following items: date of collection, shape,size, colour, morphological characters of the micropylar area, number of micropylar openings, ribbed nature of vertical and cross ribs, position and form of cellulrar markings, position and shape of aeropyles, and fine structure of the ventral surface of the egg.

In the present paper, three species of the genus Hepialus are described as new which were collected from Qinghai and Gansu Provinces. The types of 3 new species are kept in the Kunming Institute of Zoology, Academia Sinica, Kunming,China.

The present paper deals with 2 new species of the genus BlastoshrixMayr collected from Liaoning and Yunnan Provinces China. A key to the 7 speciesdistributed in China is given. The type specimens are preserved in the Department of Plant Protection, Henan Agricultural University.

This paper is the third part of a review on recent progress in insectmolecular biology. It surveys recent information on insect genes related to neurotransmitters and ion channels, Because neurotransmitters and ion channels play key roles in the transmission of chemical and electrical signals in insect ervous system,one of the major goals of insect neurobiology has been to study genes related to the structure, metabolism and function of neurotransmitters and ion channels. Some of the insect neurotransmitters and ion channels are targets of insecticide action, and the study on the neurotransmitter-related genes and ion channel genes is also a prerequisite for investigating resistance genes. The present article summarizes information on the genes involved in the cholinergic system (CHAT, Ache and AchR), GABAergic system (GAD and GABA receptor) arid biogenic amine (serotonin receptor). For the ion channels, molecular aspects of the two major voltage-gated ion channels——sodium and potassium channel genes are reviewed.