73 



3- Examine the surface of water left exposed 

 for several days in a tumbler, etc. Note, if 

 Stegomyia mosquitoes have ovi -posited, the pn-s- 

 ence of eggs occurring singly or in parallel groups. 

 Note that the ova are larger than those of Ano- 

 phelines, and that they hatch into Ciilex-like larvae 

 (see Stegomyia larvae, p. 85). 



Taeniorhynchus. — Examine natural waters, es- 

 pecially small pools with a dense growth of alga, 

 swamp pools, irrigated land, etc., for the egg- 

 rafts of Taeniorhynchus. 



1. Observe the extreme length and narrow- 

 ness of the rafts. Note also how small a portion 

 of the raft is submerged. 



2. Observe that the ova are arranged as in 

 Culex rafts with the thicker end downwards, and 

 that they are smooth and have a micropilar 

 apparatus. 



3. Endeavour to obtain the ova of known 

 species of Taeniorhynchus, by confining gravid 

 females. Note the shape of the rafts. 



Mansonia. — Observe that the eggs have a 

 curious snout- like projection, and that they are 

 laid singly. 



Psorophora. — The eggs are large, two mm. long. 

 They occur in patterns like those of Anophelines. 

 The eggs are covered with minute prickly scales. 



Taylor, in Havana, has made many observations on eggs. 

 He gives tlie following : — C. pipiens, raft 200-400 eggs ; egg 

 09 by o"i6 mm. C. nigritulus, raft 200-300 eggs ; egg o 6 by 

 o'i4 mm. U. lowii. raft 50-75 eggs. S. jasciata. Eggs laid 

 singly, about fifty in number. 



