26 



is given of the external morphology of the various stages of the genus, 

 summarising the characters common to all the species that were 

 examined. 



Cnlicoides inornalipennis, sp. n., was reared from materials taken 

 from a rot-hole in the stump of a silk-cotton tree {Eriodendron anfrac- 

 tuostim) together with other species, and from rotting materials taken 

 from the base of a banana plant, associated with several species of 

 Dasyhelea. C. schuUzei, End., was numerous on windows, while larvae 

 and pupae were found in puddles, in a backwater of a river, and in 

 rotting wood taken frt)m canoes. C. punctithorax, sp. n., was reared from 

 the rot-hole mentioned above. C. accraensis, sp. n., was taken on 

 windows, and its larvae were found in rot-holes in flamboyant 

 {Poinciana regia), silk-cotton {E. anfractnosnm) , cashew {Anacardium 

 occidentale), Cynometra sp., and other trees. C. clarkci, sp. n., was 

 reared from materials obtained from rot-holes in stumps of E. anfrac- 

 tiiosum, Cynometra sp. and another tree ; and C. confiisus, sp. n., from 

 similar material from E. anfractuosuin. C. eriodendroni was bred 

 from rot-holes in the stumps of E. anfractnosnm, Mangifera sp. (mango) 

 and another tree ; C. nigripennis from pupae in debris from a rot-hole 

 in mango ; and C. similis from material taken from a canoe. 



C. fulvithorax, Aust., C. distinctipennis, Aust., C. praetermissus, 

 sp. n., C. neavei, Aust., C. citroneus, sp. n., C. austeni, sp. n., C. grahami, 

 Aust., and C. pallidipennis, sp. n., were aU collected as adults, chiefly on 

 windows in the evening. 



Keys are given to both sexes of the species of Cnlicoides now known 

 to occur in the Gold Coast. 



Headlee (T. J). Migration as a Factor in Control. — Proc. Fifth 

 Ann. Meeting, Neiv Jersey Mosquito Extermination Assoc, 

 Trenton, 1918, pp. 104-112. ' [Received 2nd December 1920.] 



The evidence of mosquito flight is discussed, and many records of 

 previous authors are quoted. The cause of mosquito migrations is 

 obscure, but doubtless bears some relation to the necessities of food 

 and reproduction. The female usually alternates between places where 

 food occurs and where eggs may be laid. This is the type of movement 

 exhibited by the mosquitos that breed about human habitations ; 

 when, however, the same species breeds very densely over a large 

 area, it may migrate for as far as 2^ miles. In the case of species that 

 live in the wilds such as the malaria-carrying Anopheles, a distance of 

 half a mile or so may be covered in search of food, the return flight 

 being made before morning [R.A.E., B, iv, 97-99]. 



The fresh water swamp mosquitos such as Aedes sylvestris, when 

 in small numbers, seem to have the same movement as the house 

 mosquitos, such as Cidex pipiens, but w^hen breeding in great numbers 

 over a large area, may cover long distances in search of food, frequently 

 starting a fresh breeding-place in the food locality. A small brood 

 of the salt marsh mosquitos, A. cantator and A. sollicitans, will travel 

 only a short distance for food and return to the marsh for oviposition, 

 but a large one will throw off a number of migrants that will fly for long 

 distances over territory in which there is no suitable breeding-ground. 

 Intense breeding over large areas is followed by a wide distribution of 

 Cnlex pipiens, Aedes sylvestris, A. cantator, and A. sollicitans. It is 

 possible that under similar conditions some malaria-carrying Anophe- 

 lines will be found to behave in the same way. External factors, such 

 as low temperatures, light, atmospheric moisture and air movements. 



