Volucella. 399 



segments show each about three corrugations, on the first of those 

 are a pair of small warts in the middle and on the foUowing corruga- 

 tion two small spines towards each side, the one at the side margin 

 the largest; further there are on each side three short spines, one 

 upper more posteriorly, and two lower, one behind the other more 

 anteriorly; the ventral segments have a lateral spine at each side; the 

 last segment has the lateral spines surrounding the hind margin as 

 six rather long (1 — 1,5 mm) threads. It will be seen that these spines 

 are arranged as in other Syrphid larvæ, but besides them there is 

 still a small lateral spine on the corrugation wich bears the two middle 

 spines. The small hooks on the prolegs are arranged in two rows, 

 the posterior hooks smaller than the anterior. The posterior spiracular 

 process short. The length of the larva is about 20 mm. The larva 

 of pellucens is rather different; each segment is on the dorsal side 

 divided into four corrugations and these have each a transverse row 

 of numerous small spinules ; further the segments have on the second 

 corrugation two wart-like spines in the middle, and on the third 

 corrugation two towards each side, the lateral long; besides the fourth 

 corrugation has two wart-like spines in the middle similar to those 

 on the second corrugation, and the second corrugation has a long 

 lateral spine; on the sides there are the usual three spines, and on 

 each ventral segment a lateral spine; the spines surrounding the 

 posterior margin are only slightly longer than the other lateral spines. 

 This larva has thus, like that of bomdi/lans, a lateral spine on the 

 second corrugation not found in other Syrphid larvæ, but besides two 

 wart-like spines on the middle of the fourth corrugation not found in 

 hombylans or other larvæ. The prolegs are armed with relatively 

 large hooks in two rows, the anterior hooks largest. The posterior 

 spiracular process short. The size of the larva as in hombylans. This 

 larva is easily known from the larva of hombylans by all the lateral 

 spines being considerably longer, the six posterior on the contrary 

 shorter, and by the transverse rows of small spinules above. The 

 larva of zonaria (non-Danish) is, according to Kiinckel d'Herculais, 

 quite similar to that of pellucens (when fullgrown), while the larva of 

 inanis is more similar to that of hombylans but has all the spines 

 very small, scarcely perceptible, the prolegs with only one row of 

 hooks, a pair of somewhat well developed prolegs also on the meso- 

 thoracal segment and the posterior spiracular process lying more 

 posteriorly and relatively long. — The pupa of the various species is 

 rather arched, especially much arched above; it is attenuated behind, 

 broad in front; it shows the same spines as the larva; at the anterior 



