4 MEANING OF SHAPES AND COLO UPS OF THE MEMBBACID^. 



Hymenoptera (p. 535), tlie question at once arises as to whether the likeness is to 

 be exphxined by the theory oC H. W. Bates or by tliat of Fritz Miilk^r. The evidence 

 for the existence of a widesj^read distastefulness among the Heteroptera strongly 

 suggests the latter interpretation rather tlian the former. It is hardly necessary to 

 remark that there are numerous exceptions to these broad statements. Beautiful 

 examples of cryptic defence are well known in the Heteroptera even oftliis country. 

 Nevertheless the group, as a whole, is characterised by the abundance and conspicuous- 

 ness of aposematic and s3^naposematic combinations of colours, the resemblances to 

 insects outside the group falling probably into this latter category. 



The Ehvnchota Homoptkra are sharply contrasted with the Heteroptera, 

 cryptic colours and patterns being relatively common among them, although some of 

 the divisions are very conspicuous and probably aposematic. When resemblances 

 to other insects occur they are probably to be explained as Batesian (Pseudaposematic 

 = Protective) Mimicry, when the most nearly allied uou-mimetic species of Homop- 

 tkra possess a cryptic defence (Protective Eesemblance), as Miillerian (Synaposematic 

 = Common Warning Colours) when the allied species are conspicuous with 

 aposematic or warning colours. 



Allusion must be made to the special and curious defence by a waxy secretion 

 which is common in the HoMOPTERA. The method may be compared to the defensive 

 silken walls of the cocoon in other insects, while the long trailing filaments of wax 

 borne by certain species of HoMOPTERA may play the same part as the " tails " on 

 the hind wings of many Lepidoptera, or the "tussocks " of hair on some of their 

 larvae — all these probably acting as directive structures which divert the attention of 

 an enemy from the vital parts. 



The deeply interesting section of the Homoptera which forms the subject of the 

 present memoir has an important bearing upon tl>e bionomics of insect colouring, 

 aftbrding as it seems to the present writer, one of the most convincing of all the 

 arguments which have been adduced in support of an interpretation based upon the 

 theory of natural selection. 



The Mciiibraciche, as a whole, appear to depend chiefly upon Protective Resemblance, 

 concealment being effected by likeness to various vegetable structures. Examples 

 of resemblance to other insects — ants, beetles, &c. — are found in many species, but 

 the interpretation of these as Batesian or Miillerian is better considered after the 

 examples themselves have been dealt with. 



Resemblances to other insects and to the vegetable environment are, of course, 

 extremely common throughout the Insecta, but nowhere (except in a few Orthoptera) 

 are the}- produced in the same manner as in the Membracula. The deceptive disguise 

 of other insects is manifest in various parts of the body, and often in many parts 



