7526 Insects. 



remeniber whether he took it in the province of Holland, Utrecht or 

 Geldeiland. The species must be inserted between the numbers 4 and 

 5 in the catalogue. 



Nematus c^rulp:ocarpus [Hartiy). 



Imago: Hartig, Blatt. und Holzwespen, No. 8, p. 187. 



Larva : probably that described by Dahlbora under the name of 

 Tenthredo crassa, Fallen, in the ' Forhandlinger ved de skandin, 

 Naturforskeres fjerde Mode,' Chvistiania, 1847. 



Nematus niger, nitidus, mandibularum et palporum basi sordide 

 rufa, coxarum apice, femoribus et tibiarum parte majori, uecnon 

 alarum radio rufis, stigmate caeruleo-nigro, cellula lauceolata 

 pedunculata. 



In the month of September I found some larvae in the wood at the 

 Hague, on young poplars by the side of the lake. They were clinging 

 close to the petioles of the leaves : their colour and general appear- 

 ance made me think they were larvae of Hylotoma. Some years after 

 I found a similar full-grown larva on a weeping willow in the town of 

 Leyden ; and shortly after I discovered some more, in different stages 

 of growth, on some poplars outside the town. When young they ate 

 holes in the leaves, but on getting older they fed also from the margin 

 towards the midrib. They attain a length of 1 inch (fig. 1), and are 

 of a bluish green colour with brownish yellow thoracic legs : these 

 are provided with sharp brown claws. The head is pale brown, with 

 two darker stripes intersecting at right angles on the crown (fig. 3). 

 The skin is so transparent that the tracheae and their branches may 

 be easily perceived. Two dark stripes run along the back of the larva 

 as far as the penultimate segment ; in some individuals these are only 

 as it were indicated at either end. The skin is also irregularly covered 

 with black spots on the sides ; these spots run into lines, more especi- 

 ally above the legs ; from each spot grows a short bristly hair. The 

 two terminal segments are without hairs or spots, but the last has two 

 hairy protuberances on the side, near the anus, and above these, two 

 yellow horns tipped with red (fig. 3). 



After the first moult the larva is of a darker green, with blackish 

 brown head and dark horns above the anus. 



At the end of September the larvae spun up among the withered 

 leaves in neatly constructed cocoons, which on being opened appeared 

 to be double ; these were coarser on the outside, and of a dark brown 

 or deep yellow colour, oxx the inside finer and of a pale brown colour 



