io6 



ANTS. 



queen larva is merely an adaptation for accelerating the development 

 nf the ovaries i> also indicated by the fact that this insect is able to 

 lay within ten day- from the date of hatching. If this interpretation 

 is correct, the qualitative feeding of the queen larva is not primarily a 

 morphogenic but a growth stimulus. 



v The grosslv mechanical withdrawal, by parasites like O rase ma 

 ( see p. 418). of food substances already assimilated by the larva, pro- 

 duces changes of the same kind as those which distinguish the worker 

 ant from the queen, /. i\, microcephaly, microphthalmy, stenonoty and 



aptery. This case is of unusual interest because 

 the semipupa, after the detachment of the para- 

 site, seems to undergo a kind of regeneration 

 and produces a small but harmonious whole out 

 of the depleted formative substances at its dis- 

 posal. What is certainly a female or soldier semi- 

 pupa takes on worker characters while the 

 worker semipupa may be said to become infra- 

 ergatoid as the result of the sudden loss of the 

 formative substances. These observations clearly 

 indicate that the normal worker traits may be the 

 result of starvation or withholding of food rather 

 than the administration of a particular diet. 



6. The pseudogynes of Formica admit of a 

 similar interpretation if it be true, as I am in- 

 clined to believe (see p. 408), that they arise from 

 starved female larva?. Here too, the organism 

 undergoes a kind of regeneration or regulation 

 and assumes the worker aspect owing to a dearth 

 of sufficient formative substances with which to 

 complete the development as originally planned. 

 7. In the preceding cases the ants take on peculiar structural 

 modifications as the result of tolerating parasites that bring about un- 

 usual perturbations in the trophic status of the colony. When ants 

 themselves become parasitic on other ants a similar perturbation ensues, 

 but in these cases the morphological effects are confined to the parasitic 

 species and do not extend to their hosts. This must be attributed to 

 the fact that the parasitic species live in affluence and are no longer 

 required to take part in the arduous and exacting labors of the 

 colony. Under such circumstances the inhibitory effects of nutricial 

 castration on the development of the ovaries of the workers are re- 

 moved and there is a tendency for this caste to be replaced by egg- 

 laying gyn.'ecoid individuals or by ergatogynes, or for it to disappear 



FIG. 66. Ergatan- 

 dromorph of Aphcc- 

 nogaster picea ; male on 

 left, worker on right 

 side. (Original.) 



