Notes from the Sarawak Museum. 



On a Remarkable Dipterous Larva. 

 During a recent visit to Mr. Penrissen, Sarawak, I found 

 in sand beneath some overhanging- cliffs numerous small pit-falls 

 exactly like those made by the ant-lion ; some of these when 

 examined were found to contain a curious worm-like larva which 

 has since proved to belong to a fly of the genus Vermileo, family 

 Leptidre. The body consists of 11 segments, into the first of 

 which the head can be completely retracted, five annuli can 

 plainly be distinguished on segments 2, 3, and 4, but are less well 

 marked on the others ; the 10th consists only of three. The 

 middle annulusof the fourth segment bears on the ventral surface 

 a fleshy knob (abdominal pseudopod) which is surmounted by a 

 small semicircular chitinous comb longitudinally placed ; the 

 eighthsegment ventrally bears a median tuft of setae, and a fringe 

 of similar setae marks the posterior border of the 9th segment, this 

 also carries on its ventral surface 2 median setigerous papillae. 

 The 10th segment, which is set at somewhat of an angle to the 

 9th, bears on the dorsal surface at its anterior border a fringe 

 of very strong setae directed backwards. The 11th and last 

 segment terminates in four finger-like processes clothed with 

 delicate hairs, the anus opens on its ventral, two stigmata on its 

 dorsal surface. The last three segments are markedly larger 

 than any of the preceding ones. The larva burrows into the 

 sand bead first, until completely buried, and then proceeds to 

 form its pit-fall in the following manner: the more deeply 

 buried tail-end acting as a fixed point, the anterior half of 

 the body is curved about in all directions, each curving 

 motion being followed by a rapid straightening out, which jerks 

 the sand away for some little distance ; since the tail is fixed, the 

 result of many of these motions is to produce a circular repres- 

 sion with sloping sides ; at the bottom of this lies the larva, ven- 

 tral surface uppermost, the posterior half of the body still buried, 

 the anterior half exposed and straightened out. If now an ant 

 is introduced into the pit-fall, the exposed part of the larva sud- 

 denly curls up in a spiral coil, the prey being generally included 



