﻿AFRICAN SILKWORM (ANAPHE INFRACTA, WLSM.) IN UGANDA. 271 



the presence of a large percentage of dirt and foreign matter. The silk of 

 these cocoons contains less colouring matter than that of the envelopes, which is 

 probably due to the absence of light. 



The handling of the nests causes irritation to the skin, as they contain urtica- 

 ting hairs, derived from the bodies of the larvae, the effect of which on the 

 epidermis is very painful. 



Food-Plants. 



The food-plants of A. infracta are Bridelia micrantha, var. ferruyinea 

 (Luganda, " Katasemite '"), Cynometra alexandri (Luganda, " Nongo "), and 

 Triumfetta macropkylla (Luganda, " Beinsamwe ") ; and in the Belgian Congo 

 it is reported to feed on Albizzia fastiyiata. Bridelia, however, is the favourite 

 food, being invariably eaten in preference to the others. This plant is a bushy 

 shrub, attaining a height of from eight to fifteen feet, and bearing numerous 

 spines on its branches. 



Repeated attempts were made, without success, to feed the larvae of this silk- 

 worm on mulberry and on a species of wild fig (" bark-cloth tree "). It was 

 hoped that, by feeding the larvae on the former, the quality of the silk might 

 have been improved. 



Rearing the Larvae. 



The food-plant {Bridelia) can be grown either from seeds or from cuttings. 

 The latter method is preferable, as the trees attain the required size for feeding 

 the larvae much sooner, and it will be found that they grow quite readily from 

 cuttings. The trees should not be planted further apart than six feet, and it 

 may be found advantageous to adopt closer planting, for the reasons that the 

 silkworms must have plenty of shade and also must be left undisturbed, which 

 cannot be done if the trees are planted so far apart that the weeds grow readily 

 between them, necessitating constant weeding. 



When the trees are about a year old they should be "stocked" with larvae. At 

 this age each plant should have sufficient leaves to support a colony of about 

 100 larvae. The trees may be stocked either with egg-masses or nests. The 

 egg-masses are the more difficult to handle, but, on the other hand, the use of 

 nests is apt to aid in distributing parasites. When the nests have been com- 

 pleted, they may either be left on the food-plant for the adults to emerge or 

 they may be collected and removed to a specially built breeding-house. Both 

 methods have their advantages and disadvantages. If the nests are removed 

 from the trees, there is a risk of disturbing the larvae, which remain for a con- 

 siderable time in the nest without pupating, and some of them will show their 

 resentment at being disturbed by leaving the nests, and this represents a dead 

 loss of larvae. Yet, if the nests are left on the tree for the adults to emerge 

 under natural conditions, no control can be kept over the parasites which feed 

 on the larvae and pupae within the nests and which would presumably increase 

 from year to year. The question arises, therefore, whether more larvae are 

 lost through the disturbance of the nests than would be lost by the unchecked 

 depredations of the parasites ; but this is a point that cannot be settled without 



