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RESEARCH IN BRITISH WEST AFRICA. 235 



comparatively little trouble. These insects often collect in some numbers 

 during the day on the thatch inside native huts, and many may be captured 

 with a few sweeps of the net ; special attention should also be given to those 

 species which attack domesticated animals. Mosquitos may be bred quite 

 easily from larvae, and this method of collecting should be adopted whenever 

 practicable. 



The minute insects known as "sand flies" {SimuUum, Phkhetomus and 

 Culicoides) should be carefully collected. SimuUum, so far as is at present 

 known, breeds in shallow running streams. The larvae attach themselves to 

 the stems of plants and stones ; when matured, the flies are readily bred by 

 placing the larvae in situ on portions of the plant or on stones in a glass vessel, 

 which should be covered over with a piece of rubber sheeting. Water must not 

 be added or the larvae will die off rapidly. The plants or stones, however, must 

 be kept moist. Phlehotomus may be looked for in latrines anddaoif) shady places, 

 Culicoides often swarm along rivers and elsewhere ; the pierobers of this genus 

 are all minute, and examples should be preserved in alcohol as well as in a dry 

 condition. . _ 



Killing. — When the mosquitos, &c., have been brought home alive, they 

 may be killed by the method described under the heading " Brass chloroform- 

 bottle." Ammonia may be used instead of chloroform, but on no account should 

 they be shaken into the killing bottle as they are thus inevitably damaged. The 

 boxes should be afterwards left open some time before being used again for live 

 insects. 



Preserving. — For all general purposes it is desirable that mosquitos should 

 be preserved dry. Specimens to be identified must on no account be placed in 

 spirit. Mosquitos must be dealt with as soon as possible after death, for they 

 very rapidly become dry and stifi", in which state they cannot be touched without 

 breaking and are therefore useless for transmission. 



The insects may be sent home either pinned or unpinned. If pinned, the 

 following process should be adopted. Cut a small piece of paper of sufficient 

 size to write on it all data connected with the specimen to be pinned, as follows : 

 name of locality, including altitude if necessary ; date — day, month, year — thus, 

 9. XI. 98; collectors name; any remarks of interest, e.g., "Most troublesome 

 species in district," " Abundant only in open swamps," " Uncommon," &c. 

 Then take one of the fine No. 20 pins and thrust it through the middle of the 

 mosquito's thorax on the upper side, gently pushing the insect two-thirds of the 

 way up the pin and taking great care not to break off the legs ; this may 

 conveniently be effected by stretching a corner of a handkerchief between the 

 fingers and then gently pushing the pin through the fabric. 



In the case of mosquitos, a good number of specimens of each species (but not 

 more than half) should be pinned through the side of the thorax instead of from 

 above ; while the majority (say two-thirds) of the midges and sand flies should 

 be pinned in this manner. Then place the paper on a piece of cork or peat with 

 the writing downwards, seize the pin with the forceps {heUnv the specimen) and 

 thrust it through the paper, and finally, with a pin, arrange the wings so that 

 they project at an angle from the body and dispose the legs symmetrically. 

 This latter operation must be performed very gently, and care must be taken 

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