132 SANITARY ENTOMOLOGY 



breed in the flesh causing external myiasis. This species attacks ulcers 

 and sores of men and animals. Its most common attack on sheep and 

 calves is made on the soiled rumps of animals sufi^ering from diarrhea. 

 No doubt the flies also serve as distributors of the diarrhea. 



The larva has eight-lobed anterior spiracles. The same number of 

 tubercles margin the stigmal plate behind as in Calliphora, but they are 

 smaller and sharper. The stigmal plates are about one-half their 

 diameter apart, each with three straight slits, directed somewhat toward 

 each other, but also downward. 



Undoubtedly under battle front conditions this fly can be expected 

 to visit human wounds and breed in them even more readily than Cal- 

 liphora. It has been shown by Cao to transmit anthrax with equal 

 ease. 



Several other species of Lucilia have like habits, and the larvae of 

 two of these, L. caesar Linnaeus (not sericata Meigen), and L. sylvarum 

 Meigen have been described and illustrated by Banks. 



The larvae of L. caesar measure 10 to 11 mm. in length and have not 

 adequately been separated from Calliphora erytlirocephala. The larval 

 period averages about fourteen days and the pupal stage about the 

 same. Bishopp and Laake state that in Texas, during warm weather, 

 the larval period ranges from three to twelve days, the pupal stage five 

 to sixteen days and the total developmental period eleven to twenty-four 

 days. This fly is illustrated in plate I, Fig. 2. 



OTHER SCEEW WORMS AND BLOW PLIES 



The question of myiasis, which covers screw worms and blow flies, is to 

 be considered in separate lectures (Chapters XII and XIII), but mention 

 must be made of them at present because undoubtedly many infectious 

 diseases are carried by these insects which attack alike live flesh through 

 wounds, and dead animals. I would hardly hesitate to claim that 

 probably all such flies may carry anthrax at least, and probably do carry 

 other diseases. 



Bishopp, Mitchell, and Parman (1917) describe quite fully the habits 

 of the common American screw worm, Chrysomya macellaria Linnaeus * 

 (plate I, fig. 3, plate II) which breeds in both carcasses and flesh wounds 

 (plate IV). They also treat the black blow fly Phormia regina Meigen 

 (plate I, fig. 4), and other species. The large hairy blow fly, Cynomyia 

 cadaverma, Robineau-Desvoidy, and the gray flesh flies Sarcophaga 

 texana Aldrich, S. tuberosa var. sarracenioides Aldrich, S. sarraceniae 



<An appeal has been made to the International Commission on Zoological Nomen- 

 clature to retain Chrysomya in the sense with macellaria as type. 



