SUBFAMILY CHRYSOMYINAE 183 
dependent upon local, seasonal, or possibly other conditions. 
As many as 77 larvae were found upon one nestling. These were 
well distributed over the young birds, prevalent particularly 
in auricular openings, on rumps or on wings. Such parasitized 
nestlings often had the bases of the tail feathers matted with 
excrement and had blood oozing from wounds made by the 
mouthparts of the larvae. The soles of the feet and the skin 
between the bases of the toes seemed to be especially vulnerable. 
As many as three larvae were taken from the external ear open- 
ing of one bird; two engorged larvae were taken from the 
external nasal passage of another bird. Stoner discovered that 
these larvae might be found upon fledgling bank swallows 
throughout the day. The feeding larvae were not easily detached 
and the birds evidently made no effort to remove larvae from 
themselves or from each other. 
Opinions regarding effects of Apaulina larvae upon birds 
differ considerably. Appreciable injury to nestlings does not 
always result from attacks by these parasites according to 
McAtee (1929), Thomas (1939), and Sargent (1938). But they 
are considered to be a serious menace to fledglings by Plath 
(1919), Johnson (1929), and Mason (1926). Important intan- 
gible effects were noted by Mr. Edward S. Thomas in a letter, 
dated January 9, 1940, who contends that the larvae of Apaulina 
might be a contributing factor to nest desertion and that they 
may weaken some nestlings to an extent that their chances of 
survival might be seriously affected after leaving their nests. 
Mason (1936) pointed out that in New England there is a 
coincidental emergence of both Apaulina and its pupal parasite 
Mormoniella about the middle of June. 
The following species of birds! have been reported to be hosts 
of various species of Apaulina.? 
Accipiter coopert (Bon.), Cooper’s Hawk 
Asio wilsonmanus (Less.), Long-eared Owl 
Bombycilla cedrorum Vieill., Cedar Waxwing 
*This list indicates that almost every family of Passeriformes is affected 
by species of Apaulina, and it is probable that almost every species will 
be found to be similarly affected. It will be observed that the nests of the 
species concerned are of considerably diverse habitat, in a wide range of 
climate, and of very different nest construction. It will also be seen that 
although many of the species of other orders are parasitized, the number 
may be limited, at least in part, by the construction of the nest. 
"These records have been secured from the literature and the specific 
name of the parasite and the data secured from the rearing have been 
omitted. There appears to be little, if any, host specificity, and it is 
probable that any of the species of Apaulina will attack any of the above 
hosts within its own range of distribution, 
