590 PEOF. E. B. POTJLTON : NATURAL SELECTION 



larva represents the globular abdomen of tbe ant, while the head 

 and antennae of the latter are suggested by the larval caudal shield 

 with its two appendages. He believes that the disturbed larva 

 represents an aut which has seized and is endeavouring to carry 

 off some object on the branch which it is exploring. Under 

 these circumstances the head of the ant, with its mandibles fixed 

 in the object, would beheld low and remaiu motionless, while the 

 abdomen would be elevated and the legs in constant activity, 

 moving tlie posterior part of the body from side to side. Such 

 an appearance and such movements, he maintains, are strongly 

 suggested by the disturbed larva if we only identify the posterior 

 end of the one with the anterior end of the other, and vice versa. 

 I have to thank Mr. W. E. Morfill for very kindly translating 

 the memoir of the Russian naturalist. During the present 

 summer (of 1898) I have had the opportunity of studying these 

 larvae. The young larvae were thought to be ants by all the 

 friends to whom they were shown. One lady considered that 

 they were " double ants " — an interpretation evidently due to 

 their disproportionate length and to the head-like appearance of 

 the caudal shield. Drawing.s of the larvae at this stage were 

 made by Mr. P. J. Bayzand and are reproduced in fig. 2 (p. 589), 

 but they fail to convey the ant-like_^appearance which depends so 

 largely on movement. A better effect is produced by Mr. Bay- 

 zand's coloured drawing which is reproduced on Plate 40. fig. 1. 

 I should add that I did not observe any attitudes which 

 support the details of Portschinski's interpretation, nor did I 

 witness the appearances which he figures (I. c. p. 45, fig. 21). 

 His comparison of the caudal appendage with a head seemed, on 

 the other band, to be entirely confirmed. 



Turning to other Orders which supply examples of the 

 mimicry of ants, the Hemiptera have perhaps the farthest 

 distance to traA^el in the modification of their flattened bodies. 

 A beautiful example from East Africa, viz. that of Myrmoplasta 

 myra (Gerstaecker), is shown in fig. 3. Gerstaecker states 

 that a single specimen of this insect was sent from Eosako, 

 Usaramo, Aug. 1888, as "an ant," together with two undoubted 

 species of these Hymenoptera {Polyrhaclns gagates and Ponera 

 tarsata). The resemblance between the fotmer species of ant 

 and tlie Hemipteron, Gerstaecker describes as strong enough 

 to be deceptive. It is brought about, he states, by the short 

 globular abdomen extiemely constricted towards the thoiax 



