1S(>2.] 157 



cia-irc-ling tlic oxci.sii>n i« stout, so as to bo somewhat tubular (tliis is the 

 reason why, when isohited and compressed between two glass plates, this 

 opening appears less pellucid than in Mj/refoj)hi/(i). 



The combined action of the mandibles and maxillae is probably that of 

 abrading the objects against which the under side of the head is applied. 

 This may also explain the large sized upperlip, which presses these organs 

 auainst the scraped surface, and the internal situation of the lower lip, 

 which, if projecting, would interfere with the function of the other organs. 



4. Under lip. This organ is but little developed, and I have not suc- 

 ceeded in elucidating its structure completely. Between the maxillae a 

 horny, often V-shaped piece is seen (fig. 14 ; y in figs. 3 and 7 ', see, also, 

 fig. 18), the branches of which extend behind the maxillae. Judging 

 from the analogy of other insects, it is not improbable that this organ has 

 some function to perform in connection with the cocoon-spinning of the 

 larva). I incline to find this opinion confirmed by Dufour's description of 

 the larva of Ccroplatits, where these organs seem to have more develop- 

 ment. After having mentioned fico ])airi< of mandibles (evidently mean- 

 ing by the second pair the maxilla)), he describes a pair of blackish, 

 horny tubes, slightly curved, inserted, one each side, between the basis of 

 both mandibles, their tips being directed backwards. They are the organs 

 for spinning. The only doubtful point here is the position ascribed to 

 these organs, and which, if I understand it right, would not quite an- 

 swer to that of the labium. 



II. The body of the larvte of Mjeetophilidse, is subcylindrical, more or 

 less elongated, fleshy, whitish or yellowish (in Sciopliila and some Seiat-se) 

 and consists of 12 segments. It is most elongated, almost serpentiform, 

 in Sciophila ; stouter and shorter in Bolitnphila and Mijcetophila. Sciara, 

 in this respect, seems to hold the middle. It is smooth, without hairs or 

 bristles, except those on the ventral side. Generally it is very trans- 

 parent, showing distinctly the intestinal canal and the tracheae. It has 

 eiijlit pairs of stigmata,* one on the first thoracic and seven on the first 

 seven abdominal segments, the two last ones having none. These stig- 

 mata are small, horny, nipple-shaped projections; those of Sciojdiila are 

 the smallest. (At least they were so in the species I reared ; judging, 

 however, from Dufour's description and figures of the larvae of Sc. striata^ 

 it seems that the stigmata were much larger and projecting in that spe- 



■* Bouche attributes nine pairs of stigmata to the larvae of Myc. nigra and to those 

 of the three Sciarce which he reared ; Heeger, the same number to Myc. lunata. I 

 believe these statements to be erroneous, as all the larvse of Mycetophila and Sciara 

 which I saw. and likewise those described by Dufour. had eight pairs. 



