Insect Camouflage. 141 



known as mimicry. Here an insect imitates in coloration and form some 

 other insect, often of an entirely different order, which is naturally 

 protected by the possession of some unpleasant character, and by so 

 doing escapes many of its enemies. 



It will be noticed that in cases of mimicry the ' model ' already 

 possesses a coloration that is indicative of its unpleasant character 

 (warning coloration), and it is only left for the ' mimic ' to develop 

 ' special protective resemblance,' a character which has been developed in 

 every group of insects, and which we have seen is one of the most 

 primitive forms of camouflage. The two insects with their different kinds 

 of protection combine, however, to produce the most advanced form of 

 insect camouflage. 



While a large number of mimics are unprotected edible species there 

 are a great number that are themselves protected by the possession of some 

 unpleasant character, yet, in spite of this, they imitate other unpleasant 

 insects. These two different kinds of mimicry have been called after 

 their discoverers and are known as Batesian and Mullerian mimicry 

 respectively. 



Batesian mimicry is probably the commoner form and many examples 

 are to be found among our insects. 



The black Pompilid wasp with yellow antennae, Salius kirbyi is 

 mimicked by the Syntomid moth Pteryogpterus caerulevus Hmps. The 

 imitation is particularly goorl, and there is very little doubt that it is of 

 considerable advantage to its defenceless mimic ; the Pompilid ' model ' 

 on the other hand is well protected by its sting, in fact it is a predaceous 

 wasp. 



Another example of a Syntomid moth mimicking a Hymenopterous 

 insect is Saurita temenus Stoll. which mimicks the Tenthredinid 

 Monophadnus silonotus Cam. Both of these insects were taken in the 

 same locality at the same time. 



The Syntomid Trichwra cerebus Pallas, no doubt imitates some 

 Hymenopterous insect, probably an Ichneumon or Evaniid, thouo-h I 

 cannot give the ' model.' Its coloration is quite Hymenopterous-like, 

 while its long caudal appendage at once recalls the ovipositor of one of 

 these families. Taken as a whole it may be said that the family Synto- 

 midae are mimics and the Hymenoptera are their ' models.' 



It is well known that certain flies are wasp and beedike in appearance, 

 and some good examples can be found amongst our Diptera. The 

 Asilid fly Malhphora fascipennis Macq. has for its model the large bee 

 Euglossa dimidiata F. Another example is probably the Syrphid fly 

 Volucella obesa F., the model of which is perhaps a Euglossa bee, possibly 

 Euglossa cordata L. A more remarkable example is the Stratiomyid fly 

 Hermetia illucens L. The movements of this fly are very waspdike, and 



