180 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



little package attached ventrally to the base of the mosquito's 

 abdomen. They are attached by one end and point obliquely 

 downward and backward in such a way that when the .mosquito 

 sucks blood the free or hatching end is nearest the skin of the 

 phlebotomized victim. Highly significant in this connection is 

 another circumstance. The mosquitoes are preserved dry, upon 

 pins, and inclosed in small glass tubes. In one of the specimens 

 there is to be seen, adhering to the inner surface of the vial, a 

 newly hatched Dermatobia larva. The conclusion is well-nigh 

 unescapable that at the time the mosquito was introduced the 

 warmth of the hand holding the tube caused the Dermatobia egg 

 to hatch. It would thus seem, and this idea has been already 

 expressed by me in a previous paper (5), that the fully matured 

 first-stage larva remains within the egg until the mosquito has 

 found a host, the warmth given off by the vertebrate acting as 

 a stimulus to the waiting larva. The heavily chitinized con- 

 dition of the anterior half of the young larva further supports 

 this view. 



Recently a third specimen of mosquito with Dermatobia eggs 

 attached has come to hand. This was sent by Dr. Rafael Mor- 

 ales of Guatemala City. 1 Doctor Morales, it should be noted, 

 appears to have been the first to announce, in 1911, the strange 

 relation between Dermatobia and the mosquito (1), and in 

 a more recent paper (6) he has added further data in proof of 

 it. The specimen sent by him is preserved in fluid and much 

 abraded, so that its specific identity is uncertain. However, it 

 is unquestionably a Psorophora, and in all probability the species 

 lutzii.' 2 There are eight Dermatobia eggs, attached in a package 

 in exactly the same manner as in the two Venezuelan specimens 

 above described. They are attached to the mosquito and to 

 each other by means of a varnish which is insoluble in water or 

 alcohol. 



The fact that in all three specimens before me the eggs are 

 attached' to the mosquito in precisely the same manner, beneath 

 to the base of the abdomen and with the hatching end free and 

 pointing downward, leaves no room for doubt that the mother 

 Dermatobia herself thus attaches them. This is also the opinion 

 of Doctor Morales and one of his best reasons for this belief 

 is that "the eggs are firmly attached to the body of the mosquito 



1 In my previous paper I made the erroneous statement that Doctor 

 Morales is a native of Costa Rica. 



2 Doctor Morales believed this specimen to be a Culex, no doubt on ac- 

 count of the absence of striking characteristics, the scales, as already 

 noted, having been almost completely worn off. I am inclined to believe 

 that the reference to Culex as vector of the Dermatobia eggs in Doctor 

 Morales' papers is attributable to the same circumstance. 



