396 



SANITARY ENTOMOLOGY 



Fig. 74. — Bedbug: Egg and newly hatched larva: a, Larva from below; b, larva from 

 above; c, claw; (I, egg; e, hair or spine of larva. Greatly enlarged, natural size of 

 larva and egg indicated by hair lines. (Marlatt.) 



Fig. 75. — Bedbug: a, Larval skin shed at first molt; b, second larval stage immediately 

 after emerging from a; c, same after first meal, distended with blood. Greatly 

 enlarged. (Marlatt.) 



The life cycle in Cirnex hemi'pterus and C. lectularius has been dem- 

 onstrated by Patton. The parasites are ingested by the bug, enclosed in 

 the large cells or leucocytes, and develop into fully flagellated forms 

 without reference to the temperature of the external air. The size 

 increases from 4 to 7 micra and vacuolation of the cytoplasm occurs on 

 or after the second day. The single parasite may proceed directly to 

 flagellation, by the appearance of an area stained bright pink by Giemsa 

 solution and called the flagellar vacuole. This vacuole which has a dark 

 center rapidly increases in size up to 1 to 3 micra and, passing to the 

 surface, sends out a pink brush which forms the flagellum by merely 

 growing longer. Tlie flagellate form has a dark blue, granular cytoplasm 

 with a circular trophonucleus which stains deeply in the center; and a 

 kinetonucleus h'ing across the long diameter and situated near the 



