162 [March 



the anus. A short time before transforming, the larvae left their webs 

 and crawled away in different directions. Their slimy tracks remained 

 visible on the ground even when dry. The pupae were located in the 

 corners of the box, and protected by a dense web, consisting of several 

 layers; the first enclosed the pupa, the others connected both sides of 

 the corners. The pupa-state lasted only a few days, and the imago was 

 excluded fourteen days after I had first noticed the larvae. The males 

 appeared first, soon afterwards the females. (Dufour's larva did not spin 

 a cocoon.) 



It is curious that the larvae of Sciophila appeared only after the trans- 

 formation of the Mycetophilse was entirely completed ; for two or three 

 weeks the eggs of the former remained apparently dormant among the 

 bustle of so numerous larvae of the other species. This association of th^ 

 two insects seems to be of frequent occurrence. L. Dufour obtained Scio- 

 phila melanocephala n. sp., together with Mycetopliila hilaris n. sp., from 

 Fiatulina hepatica. Perris found larvae of Sciopthila together with the 

 remarkable larva of Mijc. scatophora, and if Bremi mistook the latter 

 larva for that of Sciophila, his error had very probably the same 

 foundation as that of Mr. Van Roser, — the promiscuity of the two 



larvee. 



The larva of S. limbatella is about half an inch long, very narrow, 

 snake-like, pellucid, yellowish, with some slightly darker spots ; the head 

 is yellowish, the margin of its excision brownish. The details of its 

 structure have already been given. It is strange that neither Dufour nor 

 Perris mention the palpi of these larvce. The latter says explicitly : " no 

 antennae, no palpi, no mandibles." Likewise, Perris did not discern any 

 organs of locomotion ; " not the slightest bristle, nor hair." 



Le.ta. 



The habits of these larvae, as far as known, are similar to those of 

 Sciophila. Van Roser (Verg. Wiirt. Dipt.) says of Lcja fasciola Meig., 

 " the transparent, smooth and slimy larva lives in delicate webs on the 

 surface of tree-fungi." 



In September, 1860, I found (in Virginia) under the bark of a felled 

 and decaying tree, a full-grown, white larva, living on a similar web, and 

 which may be a Leja, as sevei'al specimens of the perfect insect of this 

 genus were concealed under the same bark, in the vicinity of the larvae. 

 Some peculiarities in the structure of the trophi of these larvae have been 

 noticed above. 



