DIPTERA. 457 



FAMILY V. 



ATHERICERA. 



HERE the proboscis is usually terminated by two large lips. The sucker is 

 never composed of more than four pieces, and frequently presents but two. 



The larvae have a very soft, extremely contractile, annulated body, narrowest 

 and most pointed anteriorly. The head varies as to figure, and its external 

 organs consist of one or two hooks, accompanied in some genera by mammillae, 

 and probably in all by a sort of tongue destined to receive the nutritious juices 

 on which they feed. They usually have four stigmata, two situated on the 

 first ring, one on each side, and the two others on as many circular, squamous 

 plates at the posterior extremity of the body. It has been observed that these 

 latter, at least in several, were formed of three smaller and closely approxi- 

 mated stigmata. The larva has the faculty of enveloping these parts with the 

 marginal skin, which forms a sort of purse. They never change their skin. 

 That which invests them when first hatched becomes indurated, and thus 

 forms a sort of cocoon for the pupa. It becomes shortened, assumes an ovoidal 

 or globular figure, and the anterior portion, which in the larva was the 

 narrowest, increases in diameter, or is sometimes even thicker than the oppo- 

 site extremity. Traces of the annuli, and frequently vestiges of the stigmata, 

 are observed on it, although the latter no longer serve for respiration. The 

 body is gradually detached from the skin or cocoon, assumes the figure of an 

 elongated and extremely soft ball, on which none of its parts are perceptible, 

 and soon passes into the state of a pupa. The insect issues from its shell, by 

 removing with its head the anterior extremity, which flies off like a cap, that 

 part of the cocoon being so disposed as to facilitate this result. 



But few of the Athericera are carnivorous in their perfect state. 



They are generally found on trees, leaves and flowers. 



Their proboscis is always long, membranous, geniculate near the base, 

 terminated by two large lips, and encloses the sucker in a superior groove. 

 The upper piece of this sucker, which is inserted near the elbow, is broad, 

 arched, and emarginated at its extremity ; the three others are linear and 

 pointed, or setaceous; to each of the two lateral ones, representing the 

 maxilla?, is annexed a little membranous, narrow palpus, slightly widened and 

 rounded at the end; the inferior seta is analogous to the ligula. The head is 

 hemispherical, and mostly occupied by the eyes, that of the males particularly. 

 Its anterior extremity is frequently prolonged in the manner of a snout or 

 rostrum, receiving the proboscis underneath when it is doubled. Several 

 species resemble Bombi and other wasps. 



This tribe will comprise but the single genus 



