INSECUTOR INSClTIyE MENSTRUUS 63 



many pairs of chitinous horns. We quote from the letter: 



"There appear to be two types of egg, one terminating in 

 branched spines, the other in a single spine. So far T have 

 had three clusters deposited by confined females and all were 

 of the latter type, none of the branched or antlered type. 

 Both types occur in nature, as you will see from the examples 

 in the tubes, but the single-spined seems to be the less com- 

 mon. Apart from the difiference in the spines the eggs seem 

 the same. In tube (5) you will find newly-hatched larvae 

 from a cluster with the branched spines. They appear to be 

 those of M. titiUans and have the same habit of sticking their 

 air-tubes into the tissues of the roots, stems and leaves of the 

 Pistia. I shall endeavor to breed out adults from larvae 

 hatched from these branched-spined egg-masses, although I 

 am certain there is in our canals no other mosquito besides 

 M. titillans to which they are referable. I would also have 

 the point settled if a confined female deposits a cluster of this 

 type. 



"In the act of hatching the end of the egg bearing the spine 

 or spines breaks ofif like a cap and allows the young larva to 

 escape. From the submerged position of one of the clusters 

 laid in confinement, as well as of several found in nature, it 

 would appear that M. titillafts while ovipositing often immerses 

 at least her abdomen in the water." 



Professor Moore forwarded two female mosquitoes that 

 had deposited eggs terminating in a single stalk. These proved 

 to be Mansonia titillans beyond question, so that the simpler 

 type of egg was now definitely associated with this species. 

 These eggs may be described as follows : 



Length from 1 .0 to 1 .1 mm. ; greatest width, about 0.6 mm. 

 from base, slightly less than 0.2 mm. ; beyond this point the 

 egg tapers to a very slender tube, which last takes up about 

 0.2 mm. of the total length. The attenuation toward the basal 

 end is slightly greater than in eggs of the usual Culcx type. 

 The color is the usual pitchy brown, the distal fifth yellowish; 

 the surface is smooth, without perceptible sculpture (Fig. 1). 



The egg-mass is rounded and convex, giving the appearance 



