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found in this spot my curiosity was aroused, and looking more 

 closely I saw that the insect was an immature bug. Within a 

 short distance several other examples were found. These Mr. 



E. A. Butler has kindly determined for me as very young 

 specimens of A. alcaratus, L. In this stage the bugs are 

 remarkably ant-like, resembling most closely the common 



F. rufa, although at Beaulieu they were running about in 

 company with Formica fasca, Latr., race fusco-rufibarbis. This 

 latter ant, which was very abundant, itself somewhat resembles 

 a small dark F. rufa. On Aug. 14th I found another immature 

 Alydus in the same spot under precisely similar conditions. 



" We thus see that the same species of bug, in two different 

 phases of its life-history, mimics forms belonging to two widely- 

 separated families of the Hymenoptera. 



" Pilophorus, sp. — I have also had various opportunities of 

 observing two other species of Heteroptera which are remark- 

 xxxii] 



ably ant-like in their earlier stages. During the year 1900, 

 when I was living in St. Mary's Road, Oxford, there was in 

 the garden a rather old, diseased apple-tree, badly infested 

 with cotton-blight, Sesiids, Aphides, etc. Ants of the species 

 Lasius 7iiger, L., were always journeying up and down the 

 trunk, and in their company were many individuals of an 

 immature Capsid bug, which Mr. E. A. Butler identifies as a 

 species of Pilophorus, probably P. cinnamopterus, Kb. At 

 this stage the bugs were remarkably ant-like, and there can 

 be little doubt that this mimetic resemblance as well as the 

 companionship of the ants is advantageous to them. 



" Nabis lativentris, Boh. — At Wellington College, Berks, on 

 Aug. 10th, 1907, I found an immature example of the Reduviid 

 bug, Nabis lativentris, Boh., actually in the ant-run and in 

 company with Lasius fuliginosus, Latr. Again at Bembridge, 

 Isle of Wight, on July 8th, 1 909, another immature specimen of 

 the same species was found in company with Lasius niger. It is 

 well known that these immature bugs possess a large, whitish 

 patch on each side of the first abdominal segment, obliterating 

 its breadth and giving it the appearance of a narrow, ant-like 

 waist. This species, like the preceding, no doubt derives benefit 

 from its close resemblance to ants and association with them. 



A 2 



