WERNER MARCHAND 107 



taining wet mud, and the third water with hollow grass stems and 

 other debris. Earthworms were provided as food, but were not 

 taken very readily; the larvag seemed to prefer to eat each other. 

 They were brought to Khartoum on March 1 1 , and the following 

 morning each of the thirty-three which were still living was placed 

 in a separate jar containing clean river sand and water. They fed 

 freely on tiny earthworms, but their numbers steadily decreased 

 until about April 16, when thirteen survivors, having attained 

 maturity, ceased to feed. Up to this stage, if the sand in which they 

 were living was allowed partially to dry out, they became very rest- 

 less until water was given them again, but hereafter they preferred 

 sand which was only slightly damp. In appearance as well as habit 

 they altered considerably at this stage of their existence. While 

 young and growing, they possessed well developed prolegs and con- 

 spicuous dark dorsal markings; now, however, their prolegs became 

 small, and in color they appeared uniform yellowish white. 



These thirteen larvae were left undisturbed until May 26, when one 

 specimen was washed and was found to have pupated, probably 

 within the previous two days, as the eyes had not begun to show the 

 color which they acquired later. On the following day, two more 

 pupae were discovered in the sand. Prior to pupating the larvae 

 had made a number of tunnels in the sand, and the pupas were lying 

 in a more or less upright position in the tunnels and near the surface. 



On April 28 King left Khartoum, and traveled in the provinces 

 until May 30, by which date one larva had died and twelve com- 

 pleted their life cycles, producing eight females and four males. 

 The first had emerged on April 29 or 30, so the period passed in the 

 pupal stage was probably about six days. 



King's detailed description is given in about the following words. 



Immature Larva. — (Plate 3, Fig. 47; Plate 4, Fig. 57, a-d.) Length 18 

 mm. Color yellowish white, with dark markings composed of pubescence. 

 Mandibles dark brown to black, slightly serrated. Anterior margins of the 

 meso- and metathoracic segments dark, except on the venter. A ring of pseudo- 

 pods, eight in each ring, two dorsal, two lateral, four ventral, on the anterior third 

 of each abdominal segment except the eighth, well developed, except the dorsal 

 pairs on the first and second segments, and bearing spines or hooks. Spines are 

 also present between the pseudopods on each ring. The rings on the first and 



