PREDACEOUS CHIEONOMID LARVJ3 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 MegarMnus lars^se 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 larvae 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 larvae in each beaker. They were fed upon the larvae of smaller 

 species, chiefly A'edes calopus and Culex sp. The observers stated that the 

 Megarhinus larvae swallowed the smaller larvae 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 salinariu-s 

 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 suflBced. 



The larvffi of the culicid subfamily Corethinae are predaceous and some of 

 them feed extensively upon mosquito larvae. In northerly regions the larvae of 

 Corethra {Moclilonyx auct.) appear simultaneously with those of A'edes 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 larvae of Chaohorus (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 larvae 

 to some extent. Thus one of us (Knab) has found the larvae of Chaohorus 

 punctipennis in a temporary puddle preying upon the larvae of Culex pipiens. 

 Plate VIII, figs. 1-3, shows the larvae of Chaohorus and Corethra. 



The larva of another non-biting mosquito of this subfamily, Eucorethra 

 underivoodi, has been found by W. L. Underwood to feed upon the larvae of other 

 mosquitoes, and this has been abundantly confirmed by other observers. On 

 one occasion Mr. Underwood found that fourteen of these larvae ate over night 

 sixty out of seventy mosquito larvae that had been placed with them. He says 

 (Popular Science Monthly, Sept., 1903, p. 466) : "When eating the larvae 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 larvae of many neraocerous Diptera are predaceous and doubtless 

 many of these capture mosquito larvae along with other prey. The larvae of 

 certain Chironomidse, 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 



