from the Rio Nautla, State of Vera Cruz. 289 
present known. ‘This is particularly the case when collect- 
ing is done every day for a considerable length of time, and 
done closely. From June 18 to July 20 I collected daily all 
the Diptera possible, especial attention being given to the 
Cordia flowers. It has been thought that, in the tropics 
especially, dates are of little or no consequence; but I ob- 
served at San Rafael, during my close collecting daily from 
early spring to midsummer, that as the season advanced very 
many species of insects appeared suddenly, where before 
there had been none at all to be found. This shows that 
species have their seasons in the tropics as well as in colder 
latitudes, a fact which is evident enough to anyone who has 
collected carefully for any length of time in tropical regions. 
Hippoboscide. 
LIPOPTENA. 
Since the time when, in 1823, more than seventy years 
ago, Say described Lipoptena depressa taken from Cariacus 
virginianus in Pennsylvania, no mention has, to my know- 
ledge, been made of further specimens of this genus from 
America. It will therefore be interesting to know that I 
secured between one and two hundred specimens from a 
Mexican white-tailed deer near Paso de Telaya. 
45. Lipoptena depressa, var. mexicana, var. n. 
Numerous specimens of both sexes, 153 in all, together 
with puparia, taken from ventral region, hind quarters, and 
sides of a white-tailed deer, Cariacus virginianus, var. 
mexicanus, March 27. Paso de Telaya. 
The specimens agree fairly well with Say’s description of 
depressa. ‘Vhe antenne are yellowish. I can distinguish no 
brown lines on hypostoma, unless Say and Wiedemann refer 
to the two halves of the labrum which might have been ap- 
pressed to the under surface in their specimens, or to the 
two linear spots above on each side of base of labrum. There 
are often, doubtless normally, three soft brownish longitudi- 
nally-elongate spots on posterior portion of tergum, the middle 
one the largest and heaviest, and situated a little farther 
posteriorly than the lateral ones. The middle one is often 
heightened, and the lateral ones obscured, by the developing 
larval case or puparium within the abdomen of the female, 
thus giving the appearance of a single heavy dark spot. All 
the specimens are wingless, but the wings are represented by 
well-deweloped rudiments. The lateral pointed elytra-like 
