PREDACEOUS CHIRONOMID LARVZ 169 
stracted without swallowing the chitinous epidermis. This specimen was kept 
for hours in a few drops of water on a watchglass, for observation under the 
microscope, and was very lively when put back with the others.” 
The predaceous habits of Megarhinus larvee have been noted by observers in 
both hemispheres. The feeding-habits of the larva of Megarhinus septentrio- 
nalis, have been studied by Morgan and Cotton. Twenty-four larve of this 
species were collected by Professor Morgan in a half-barrel of rain-water and 
carried to his laboratory, where they were placed in beakers containing tap- 
water, several larvee in each beaker. They were fed upon the larve of smaller 
species, chiefly Aédes calopus and Culex sp. The observers stated that the 
Megarhinus larve swallowed the smaller larve bodily, but when feeding upon 
one another the victim was held in the strong mandibles and slowly devoured. 
They made no effort to pursue their prey but remained quietly near the bottom 
of the water until a smaller larva approached, when it was seized with a quick 
movement and speedily devoured. No effort was apparently made to change the 
hold, whether the prey was seized near the head, near the middle or posteriorly. 
One Megarhinus was seen to seize a nearly mature larva of Culex salinarius 
near the middle, and without loosening its hold to swallow it gradually, the head 
and tail disappearing together. When swallowing the prey head foremost, there 
was much difficulty, and in one instance it took an hour to swallow one in this 
way, whereas usually three or four minutes sufficed. 
The larve of the culicid subfamily Corethine are predaceous and some of 
them feed extensively upon mosquito larve. In northerly regions the larve of 
Corethra (Mochlonyx auct.) appear simultaneously with those of Aédes in the 
snow-water of early spring; they prey largely, if not altogether, on these and 
must act as a check to some extent. The larve of Chaoborus (Corethra auct., 
Sayomyia Coq.) occur under more varied conditions and their food appears to 
consist mostly of small crustacea; they do, however, feed upon mosquito larve 
to some extent. Thus one of us (Knab) has found the larve of Chaoborus 
punctipennis in a temporary puddle preying upon the larve of Culex pipiens. 
Plate VIII, figs. 1-8, shows the larve of Chaoborus and Corethra. 
The larva of another non-biting mosquito of this subfamily, Hucorethra 
underwoodi, has been found by W. L. Underwood to feed upon the larve of other 
mosquitoes, and this has been abundantly confirmed by other observers. On 
one occasion Mr. Underwood found that fourteen of these larve ate over night 
sixty out of seventy mosquito larve that had been placed with them. He says 
(Popular Science Monthly, Sept., 1903, p. 466) : “ When eating the larve of 
mosquitoes smaller than themselves, the victim is caught, shaken violently a 
few times, and swallowed in a few seconds in very much the same way that a 
pickerel would catch and swallow a smaller fish.” 
The aquatic larve of many nemocerous Diptera are predaceous and doubtless 
many of these capture mosquito larve along with other prey. The larve of 
certain Chironomid, particularly those of the genus Tanypus and related 
genera, have long been known to be predaceous. The digestive tract of certain 
European species has been found to contain red coloring-matter, suggesting that 
