418 Mr. Wzesrwoop's Illustrations of the 
prevents a positive assertion upon this point*. The variations, however, ex- 
isting between these two groups in the important organs noticed above is so 
great, that, in comparison with the structure of other allied tribes, it must be 
admitted that we here find the real characteristics of an analogy, namely, ex- 
ternal similarity of form, but a complete diversity of structure in the essential 
organs. 
The examples hitherto produced have exhibited analogies existing between 
insects belonging to the same order. In this latter respect, however, (or, in 
other words, on account of their Coleopterous structure,) they are related 
together by affinity. 
Of the still more widely extended relationship resulting from analogy, many 
examples might be given. Some have already been noticed in the introductory 
remarks upon the genus Diopsis, published in the last volume of the Trans- 
actions of this Society. Others may be mentioned wherein a great enlargement 
either of the scutellum or the posterior part of the prothorax is observed, 
which, contrary to the ordinary structure, is extended entirely over the body 
and wings. The genus Scutellera (so named from this ci rcumstanee) amongst 
the Heteropterous Hemiptera, many Centroti, &c. amongst the Homopterous 
_ Hemiptera, the species of Acrydium (Tetrix, Latr.) in the order Orthoptera, 
Thorocantha, Latr., in the Hymenoptera, and Celyphus, Dalm. in the Diptera, 
respectively exhibit this singularity of formation. 
The curious genus Copium, Thunberg (Holhymenia, Serv. and St. Farg.), is 
strikingly represented amongst Dipterous insects by the insect which I have 
figured in Griffiths's “ Animal Kingdom” under the name of Diateina Holhyme- 
moides, and in which the structure of the antennæ, and even the white colour 
of the terminal joints, are especially traceable in a most singular manner. 
The Neuropterous genus Ascalaphus in like manner analogically represents 
the genus Papilio in another Order, Lepidoptera. 
instance which I have hitherto met with, of decepti 
of one order assuming the appearance of another, 
But the most complete 
on produced by an insect 
occurs in the species about 
