172 
Psyche 
[September 
buzzing sound. It made several attempts to alight on the 
belly of the mule but each time it struck with so much force 
and noise that the animal flinched and twitched its skin to 
prevent it. After a number of trials it succeeded in alight- 
ing on the inside of the upper part of the hind leg and began 
to feed. This gave me a chance to capture it. A second 
specimen was also seen making several efforts to alight on 
the mule but, like the first one, it struck so forcibly and nois- 
ily that it startled the animal each time and caused it to 
flinch and stamp its feet. The fly finally ceased its attempt 
to alight and flew away. It did not return while I was ob- 
serving the mule. 
Lepidoselaga lepidota Wiedemann. Three of these flies 
were captured inside the camp at Camp Pital. They were 
taken some days after our arrival and apparently had 
gained entrance through holes in the screening or while the 
doors were open. A fourth specimen was captured as it 
was feeding upon an ox in a pasture near Esperanza Sta- 
tion. Since this species appears to pass its larval and pupal 
stages at the base of the crown of leaves of the water let- 
tuce, Pistia stratiotes, it is quite probable that these flies 
were much more numerous in closer proximity to rivers, 
streams, pools, etc., in which these plants were present. 
Chrysops melsenus Hine. Twenty-four flies of this species 
were captured while they were feeding upon the mule at 
Camp Pital. They seemed to confine thier attacks mainly 
to the region about the animal's ears. 
Chrysops calogaster Schiner. One of the small flies of 
this species was found inside the camp at Camp Pital upon 
our arrival. 
Dichelacera analis Hine. Flies of this species were found 
to be much more numerous than any other of the Tabanidse 
and were the most persistent in their attacks on man and 
animals. A total of 165 specimens were collected at Camp 
Pital and Puerto Armuelles. Twenty-two of these were 
found inside the camp upon our arrival, where they had 
entered apparently for shade. The remainder were taken 
while biting either man or the mule. They were present 
