54 



been described as a separate species by Costa under the name of 

 Nobis myrmicodes, having reference to its mimicry of an ant. 

 and indeed very happily so named. In the parks and leafy 

 woods in places around Lille in the north of France, I happened 

 to net, in some shady groves, a considerable number of the 

 nymphs of this species, from 2-4^ miflimeters long; in the net 

 with the same were numbers of a Myrmica, the species of which 

 I did not determine ; these individuals, though systematically so 

 far apart, could scarcely be separated then. Towards the mimick- 

 ing of the Myrmica, there contribute in a high degree the four 

 upright spines in the nymphs, one on each side of the meso-and 

 metathorax ; the abdomen is not itself so extraordinarily con- 

 stricted at the base, but it appears so, by reason of the white 

 spots, placed one on each side at the base. This is the case 

 actually in the young nymphs, which have need of the mimicry, 

 but in the older ones it is less marked, owing to the four white 

 spots above-mentioned disappearing (15), The species has by 

 that time become very big, so that mimicry of an ant would be 

 of utility no longer, as the latter are not so large. The colour- 

 ing of the small individual is also more in accordance with that 

 of the Myrmica. Coriscus lativcntris is a predaceous bug whose 

 lifehistory, and the nature of its relations with the ants, are as 

 yet unknown." 



More recently, Breddin, in a paper entitled ''Nachahmungser- 

 scheinungen bei Rhynchoten" (14) has also discussed this spe- 

 cies. He says: "Figure I shows a blackish-brown insect the 

 proportions of whose body cannot in the least be compared with 

 those of an ant. But through a real stroke of genius on the 

 part of Nature ( !) this little animal is wonderfully clothed. 

 On each side of the base of the abdomen there appears a whitish, 

 faintly glittering spot which extends far across the back until 

 the dull ground-colour appears only as a narrow central stripe 

 which is very much like the well-known stalked abdomen of the 

 ants. In order to make the masquerade complete, the plump 

 and conspicuous anterolateral parts of the abdomen are made 

 invisible by the little white spot, and the transformation of the 

 really plumply built insect into a slender ant, is complete. 



"This adaptation is very much more marked than in the col- 

 ouring or the nymphs of the other species of Nabis, especially in 



(15). They occur in nymphs of 4% mill, long, not any longer in 

 those of 6 mill, length. 



