162 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



ture or chitinization for the protection of the integument in 

 the open, are necessarily deposited on the body of the host. 

 But there is a considerable class of hosts to which the fly is 

 denied access, due to the nature of their habitats within sub- 

 stances that the fly can not penetrate. Such are wood-boring 

 grubs within the trunks of trees, white grubs and others be- 

 neath the surface of the soil, weevil grubs and others within 

 the various fruits of plants, borers and miners within the 

 fleshy parts of plants, and various other protected hosts of a 

 similar nature. The ingenuities of parasitism have triumphed 

 over the isolation of these hosts, and the flies deposit their 

 maggots as near to them as they are able to approach, leaving 

 the rest to their progeny. The maggots reach the hosts for 

 themselves either by penetrating the soil, following the gal- 

 leries of borers, or burrowing into the substances of plants 

 and their fruits, in short following the hosts where the flies 

 cannot enter. As these maggots are not exposed to open 

 conditions they do not need iutegumental specialization. 

 Thus certain of the forms here grouped by Pantel, as for in- 

 stance Leskia aurea, do not necessarily larviposit on the host. 

 The true dexiine flies exhibit the largest number of forms 

 parasitic upon hidden hosts, such as white grubs, woodborers, 

 and weevil grubs in various pods, nuts, and fruits. 



Pantel's consideration of the role of the maternal organs in 

 intrauterine incubation is of interest. He considers the possi- 

 bility of the tubular glands functioning as suppliers of nutri- 

 ment, and the possibility of an osmotic supply through the 

 walls of the uterus from the maternal blood. I believe that 

 both of these methods may occur in the case of Glossina an,d 

 other forms that carry the maggot through one or more stages 

 in the uterus, but I do not think they occur during the de- 

 velopment of the embryo. The uterus probably acts merely 

 as a mechanical container during the latter period. The nu- 

 tritive supply which provides for the development of the ova 

 in the ovarioles must be derived either directly or indirectly 

 from the blood, perhaps through the fat-body; once formed 

 and fertilized, the egg probably contains all the elements and 

 nutritive supply necessary for the full development of the 

 maggot. 



Group VII. Species introducing into the body of the host, 

 by means of separate instruments of perforation and injection, 

 naked maggots or maggots in choria. This is the group of 

 Compsilura and its allies, having the habit of subcutaneous 

 larviposition. It is a very natural group, but with only the 



