M. Bezzi 
35 
Musca chrysorrhoea, ? Meigen, 1826, p. 60. 
Calliphora chrysorrhoea, Macquart, 1835, p. 263; Schiner, 1862, p. 585; 
Brauer, 1883, p. 74; Strobl, 1894, p. 70; Brauer and Bergenstamm, 1894, 
). 546. 
Protocalliphora chrysorrhoea , Hough, 1899, p. 289; Aldrich, 1905, p. 524. 
Avihospita chrysorrhoea , Hendel, 1901, p. 29. 
, Avihospita n. sp., Hendel, 1901, p. 30. 
Phormia chrysorrhoea , Tyler Townsend, in Plath, 1919, pp. 374 and 380. 
? Calliphora splendida , Macquart, 1845, p. 324. 
Phormia caerulea , Kramer, 1917, p. 27. 
Geographical distribution. This fly has apparently the same distribution in 
Europe as the other species, but is much more rare and there are only a few 
orecise records, those of all the earlier writers being in my opinion very 
ioubtful. It has been assumed here that the descriptions in which the 
sexual dichroism is not clearly indicated, apply to the true azurea , because 
Fallen’s original description refers to a species in which the males and the 
r emales are equally coloured. But even in this last case a confusion with 
Vrotophormia terraenovae , R.-D., is always possible. The species is also recorded 
:rom North America, its distribution there being not yet determined. 
Ethology. The larval stages were described by Engel in 1920, and compared 
with those of caerulea. The habits of these larvae seem to be the same. Engel 
has obtained the species from subterraneous nests of Riparia riparia, and this 
is the unique precise record, which indicates a very peculiar habitat. 
3. Protocalliphora metallica (Tyler Townsend). 
Phormia metallica, Tyler Townsend, 1919, p. 379; Plath, 1919, p. 376. 
? Protocalliphora azurea, Coutant, 1915, p. 145. 
Geographical distribution. This species as far as it is known is exclusively 
a North American one; its range extends throughout the United States 
chiefly in the East, being very rare in the West. It is possible that the above 
mentioned splendida, Macquart, from Texas, may be synonymous with the 
present species. 
Ethology. Plath found the larvae in nests of Merula migratoria. The larva 
from nests of Corvus americanus fully described by Coutant, may possibly 
belong to the present species; at any rate this larva cannot be that of azurea 
or of caerulea owing to the very important differences pointed out by Roubaud, 
1918, pp. 423-424. 
* * * * 
The larvae of the above named species of Passeromyia and Protocalliphora 
live in bird nests, and attracted by positive thermotropism to the naked 
bodies of the young nestlings, they can suck their blood. But this type of 
intermittent haematophagy makes it impossible for them, as shown by Dr Rou¬ 
baud, to become permanent parasites. There are however several records 
of fly-larvae found in subcutaneous tumours on young birds and attributed 
3—2 
