M. anomala the frons is a little narrower, and the reddish frontal 
tnangle disappears upwards, while in M. torquans the latter is fairly 
distmct up to the vertex; in the female the frons is considerably 
narrower than in M. torquans , and the middle stripe not broader than 
the sides; the sides and the cheeks are yellow in M. anomala and 
sil very in M. torquans ; finally the female of M. anomala has the 
legs coloured like the male, while in il I. torquans they are darker. 
Besides this there is also a biological difference between the 
two species. As above mentioned Mr. Mogensen has based his 
opinion of the distinctness of M. anomala upon the faet, that the 
larva produces a cocoon, and he has told me, that he never 
observed such cocoons by his breedings of M. torquans . After this 
we can admit, that the last named species pupates without cocoon. 
In my previous paper I have mentioned a few literary records of 
dipterous larvæ parasitic on birds. Among these there are two 1 ) 
in which the authors record the cocoon making habits of the larva 
of Aricia pici Macq. 2 ). Also Au g. Busck 3 ) mentions that Mydæa 
pici Macq. pupates in a cocoon of particles of earth glued together 
by a glistening white exeretion, while Townsend 4 ) in a paper' 
containing the description of Mydæa spermophilæ n. sp. does not 
mention a cocoon. As it is possible that there are more Mydæa 
species of parasitic habits I shall not make any attempt at identifying 
the flies mentioned by the said authors with my two species as 
I have not had the opportunity of seing the type specimens. 
Macquard: Notice sur une nouvelle espéce dAricia (Ann. d. la Soc 
entom. de France 3. Serie I. 1853. p. 655). 
R. Bl an ch ard: Contributions å l’étude des Diptéres parasites. Troi- 
siéme série. (Ibid. LXV 1896 p. 652). 
) After the determination of the late Prof. Brauer the fly which has 
foimed the object of the investigations of Prof. Blanchard is identical 
with M. anomala Jaenn.; it is sure that Aricia pici Macq. is a My¬ 
dæa, but the species is not recognizable alter the description and the 
figure of Macquard. 
3 ) Au g. Busck: Mydæa pici Macq. (Proc. Entomol. Soc. Washington 
VIII. 1906 p. 2). * 
4 ) C. Th. Townsend in Transacts. Amer. Entom. Soc. XXII 1895 p. 79. 
