BED-BUGS. 231 



frequently transferred with wash clothes. They have a penetrating 

 odor. The eggs are deposited in cracks and in 10 days they hatch out 

 into larvae which pass insensibly into adults by a series of moultings 

 (5). The bed-bug is very probably the intermediate host in kala azar, 

 and it has been incriminated in connection with typhus fever and 

 relapsing fever. 



Reduviidae. 



Conorrhinus sanguisuga. This is known as the Texas or 

 Mexican bed bug, and was formerly the foe of the common bed-bug, 

 but having gottten a taste for human blood through the Cimex or 

 Ancathia, it now prefers man. It is extending toward the North. 

 It has wings. The bites are much more severe than those of the com- 

 mon bed bug. It is of a dark brown color, nearly an inch in length, 

 with a long, flat, narrow head and a short thick rostrum. They can 

 run as well as fly. They bite at night. 



DIPTERA. 



The order Diptera is of great importance medically in a variety of 

 ways, either by the direct irritation of their bites, by their transmitting 

 disease directly, as does the common housefly typhoid fever, or by 

 acting as intermediate hosts for various parasites. They are character- 

 ized by mouth parts formed for puncturing, sucking or licking. They 

 present a complete metamorphosis, larva, pupa and imago. As a 

 rule, the diptera have a distinct pair of wings, the second pair being 

 rudimentary. With the Aphaniptera the wings are practically absent. 

 Under the Aphaniptera, \ve have to consider the Pulicidae or flea 

 family. 



Pulicidae. 



This family is divided into 2 subfamilies the Pulicinae and the 

 Sarcopsyllinae. In the former the female remains practically un- 

 changed after fecundation, in the latter the abdomen becomes 

 enormously distended with eggs, and the female remains stationary after 

 her impregnation in the burrow which she has made under the skin. 



