GASTROPHILUS HAEMORRHOIDALIS AND OTHER BOTS. 33 
observed feeding upon flowers, but green twigs were favorable resting 
places in rearing cages. 
_A female taken while ovipositing was placed within a tube contain- 
ing a male, and they were observed to copulate for 5 minutes. 
Dissections.of 5 females showed the following egg capacity: Maxi- 
mum, 770; minimum, 397; average, 541. 
INCUBATION AND INGRESS OF LARV. 
While making observations in pastures, on four occasions large 
numbers of eggs were collected which had been deposited upon the 
author’s horse. The eggs were kept in tubes at air temperatures of a 
living room and none hatched without friction and moisture. By 
placing the infested hair upon a microscope slide and moistening it 
the larve were most easily removed by rubbing the lot with a dis- 
secting needle. In such tests the eggs remained attached to the hair, 
while the operculum was removed, allowing the larva to emerge. 
Very good results were also obtained by rubbing a moistened finger 
over the lot. When eggs were less than 7 days old it was found diffi- 
cult to obtain living larve, though at 9 and 11 days active larve were 
removed. When they were slightly older than 11 days they emerged 
without difficulty when attended by moisture and friction, and one 
living larva was found as late as the forty-eighth day. This seemed 
to be an exception, as in the other lots all were dead after 40 days. 
In general, all experiments tended to confirm those of Osborn. Ac- 
cording to Guyot, with various lots placed in paper bags and kept 
in a pasteboard box at room temperatures, some emerged without 
moisture and friction. On December 28, 1900, Guyot obtained 
quite agile larve as late as 96 days after collection of the eggs. 
In another case, with eggs collected on October 6, he succeeded 
in obtaining larve from January 7 to 13 following, a period of 92 
to 98 days. Due to this fact, Guyot concludes that the larve are 
capable of withstanding comparatively low temperatures after the 
egos have been removed from the host. From eggs collected on 
(=) . 
horses in the open, active larvee were removed as late as December 1. 
LARVA STAGES. 
The attachment of young larve frequently occurs in almost any 
part of the stomach, but, as has been previously stated, they are 
found as fourth-stage larvee upon the mucosa of the stomach, more 
especially on the left sac. If living larve are removed from an 
animal during a post-mortem examination a great tendency for re- 
attachment will be observed. During such examinations they have 
been frequently separated into lots according to species, and in a short 
