UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 19, No. 5, pp. 191-200 February 7, 1919 



A MUSCID LARVA OP THE SAN FRANCISCO 



BAY REGION WHICH SUCKS THE BLOOD 



OF NESTLING BIRDS 1 



BY 



O. E. PLATII 



Up to the middle of the nineteenth century it was generally believed 

 by zoologists that all museid fly larvae were scavengers living in and 

 depending upon decomposing animal or vegetable matter. The first one 

 td point out that this belief is erroneous was the French scientist Leon 

 Dufour (1845). In the spring of 1844 while examining a brood of young 

 swallows this French scientist accidentally came across some fly larvae 

 and pupae, the adults of which were later identified as Calliphorinae 

 belonging to the species Lucilia dispar. He noticed that the larvae were 

 "gorged with blood," and concluded that they were external blood- 

 sucking parasites and not scavengers, as most fly larvae are. Since 

 then a number of similar cases of parasitism by the larvae of Proto- 

 calliphora azurea (Fallen! and Protocalliphora chrysorrhea < Meigen) 

 have been recorded by other scientists (see Coutant, 1111"), pp. 138- 

 150) ; and within the last decade or two it has been discovered I Austen, 

 1907. and Roubaud, 1913) that the larvae of several African flies 

 belonging to the Calliphorinae habitually suck the blood of mammals, 

 such as the aard-vark and wart-hog, and even man, and that they are 

 absolutely dependent upon vertebrate blood in order to mature. 



In the summer of 1913 I accidentally discovered some sixty or 

 seventy fly larvae and pupae in two nests of goldfinches, one belonging 

 to the species Astragalinus psaltria hesperophilus Oberholser and the 

 other to Astragalinus tristis salicamcms (Grinnell). The two nests 



i A popular and more comprehensive paper on this subject is to appear in the 

 January-February number of The Condor for 1919. 



