880 Charles Paul Alexander 



just described, the writer found larvae and newly transformed pupae in 



great numbers, the former pupating in the dry sand rather distant from 



the water's edge. In one dry patch of sand on a rocky ledge, sixty 



specimens were found in six square inches of soil. The insects are often 



found in gravel or coarse sand that is thickly penetrated by grass roots 



and rhizomes, rarely in pure gravel. The}- are most commonly found 



in soil that has l)een recently deposited after freshets. The immature 



stages of Hcxatoma are associated ^^dth larvae of Eriocera spinosa, E. 



cinerea, Tipula bella, and Atherix probaljly variegata Walk., with pupae 



of Chrysops excitans Walk,, and with many beetle^ such as Paederiis 



littoran'us Grav., Gastrolohium bicolor (Grav.), Bledius sp., Omophron sp., 



Dyschiriics sphaericoUis Say, Tachistodes partiarius (Say), Anadaptus 



discoideus (Dej.), Laccobius agilis Rand, and other species characteristic 



of the sandy margins of large streams. The pupal duration of Hexatoma 



is six and one-half days. 



Larva. — Length, 14-15 mm. 

 Diameter, 1-1.3 mm. 



Color of body, pale brownish yellow. 



Body covered with rather abundant appressed hairs, the subterminal distended part of 

 abdomen with transverse rows of very short spines or setae, there being from thirty-five to 

 forty such rows. Spiracular disk (Plate LI, 246) surrounded by four lobes; ventral lobes 

 the longer, with a fringe of a few long hairs at apex; on inner face a long, narrow, brown 

 mark, extending from the tip inward, the proximal end expanded; lateral lobes with numerous 

 long hairs which are gradually shorter toward base of lobes. Spiracles circular, situated at 

 base of lateral lobes; a dusky mark extending from spiracles dorsad. 



Head capsule of usual hexatomine type, as described for Eriocera longicoriiis (page 888). 

 Entire general features and details of mouth parts very similar to those of Eriocera longicornis. 

 Labrum (Plate LI, 243) transversely oval, with frame strong and chitinized, anterior median 

 part produced into a small lobe (Plate Lll, 250) bearing two lateral papillae and two setiferous 

 tubercles surrounded by short hairs; lateral margins of labrum produced into prominent 

 lobes directed proximad and cephalad, densely hairy and entirely protecting anterior margin 

 of labrum. Antenna (Plate LI, 244) with apical papillae shorter than segment, the largest 

 papilla transversely sculptured (Plate LII, 251). IMandible (Plate LI, 245) long and slen- 

 der, the lateral teeth more accentuated than in Eriocera; largest tooth with a flattened trun- 

 cated blade in its axil, this in some cases broken up into two or three small blades; basad 

 of largest lateral tooth a flattened lobe which is barely indicated in the species of Eriocera 

 studied. Maxilla with outer flattened blade conspicuous; palpus near its base on inner 

 side, similar to the condition obtaining in Eriocera; just laterad of palpus a powerful seta. 



Pupa. — Length, 9.2-9.6 mm. 

 Width, d.-s., 1.2 mm. 

 Depth, d.-v., 1.4 mm. 



