72 Journal New York Entomological Society. [Voi.xm. 



influence of indoor temperature, soon pupated and the first imago ap- 

 peared upon March 15 after a pupal period of three days. Larva; of 

 this species were collected from Sarracenia leaves by Dr. A. D. 

 Hopkins at Boardman, N. C, on April 4, 1904. 



In the collection of the Illinois State Laboratory of Natural History 

 are larva; taken from leaves of Sarracenia purpurea at Cedar Lake, 

 Illinois, on June 19, 1892. From the data given it appears that the 

 larva? may be found at all seasons of the year and that there are no 

 well marked broods. Development proceeds more or less rapidly, de- 

 pending upon the necessarily variable food supply and upon the tem- 

 perature. Like the larva of Wyeomyia that of Metriocncmus is 

 extremely hardy and can linger a long time without food. Of those 

 collected in August, and kept in the original liquid in a tin covered 

 breeding jar, some were still alive early the following April and some 

 few of these completed their transformation ; the remainder however 

 were all dead by the end of the month. 



Following are descriptions of the larva and pupa of Metriocnemus 

 knabi. 



Larva (fig. 1). Form long and slender, of the ordinary chironomid type. 

 Length about 7 mm. Color very pale yellow, the head and the appendages of the 

 ninth abdominal segment bright brownish yellow. The body is sufficiently translu- 

 cent to permit the dark digestive tract and the tracheal tubes (in the form of two sil- 

 very sinuate lines) to be readily seen. The tracheal tubes are well developed and 

 may be distinguished through their whole course, until they break up into finer 

 branches in the head and in the ninth abdominal segment. Head rather small, 

 longer than wide, tapering slightly towards the front. The foramen very wide, 

 broadly margined with black. Clypeus prominent, about half the width of the head. 

 Eyes small, in front of the middle, almost lateral. Antennre (fig. 2) inserted well 

 forward, rather prominent, of four segments ; the basal segment large and stout, 

 about three times as long as wide ; second segment very slender, about a third the 

 length of the first ; third segment still more slender and shorter than the second ; 

 fourth segment very small and slender, tapering to a point ; upon the apex of the 

 basal segment, inserted beside the second segment, is a large spine or appendiculate 

 segment equalling in length the three outer segments. Mandibles (fig. 3) promi- 

 nent, stout at base ; the outer half slender, curved, tapering to a point and with four 

 teeth upon the inner margin ; basal portion greatly dilated and hollowed out, with a 

 large opening upon the inner side ; attached to the inner side near the base is a fan- 

 shaped brush of 7 or 8 long hairs with a common base. Labrum (fig. 4) large and 

 rounded, hinged to the head by a narrower flexible strip ; the front of the labrum 

 projects over and bears a number of spines and setie ; beneath, well forward and 

 medianly, is a group of curious ciliate appendages and outward from these, a pair of 

 stout curved appendages with densely tufted apices projects downward. These last 

 mentioned appendages appear to correspond to the "mouth tufts" of mosquito 

 larvae. Beneath, the head is flattened and the epicranial plates are completely fused. 



