BRODIE ON FOSSIL INSECTS. 401 



All these are small and ill defined ; and although it is difficult from 

 such fragments to define the condition of the imago, it is evident 

 that most of the species were not aquatic in their habits, many, on 

 the contrary, belonging to lignivorous or herbivorous species, and 

 some being evidently elaterideous, while others may be carabideous. 

 There are in the collections examined two or three instances of 

 legs, all of which seem to have belonged to the slender-footed 

 family of grasshoppers ; and the collection also includes about 

 thirty specimens of the detached abdomens of various beetles, all 

 of comparatively small size, not more, in fact, than one third of an 

 inch in length. 



Of detached wings from the lias, there are about eighty spe- 

 cimens, including Libellulidce, Ephemeridce, Hemcerobiidce, Panor- 

 pzdce (?) together with others, distinguished by the arrangement 

 of the wing veins, which are also found in the wealden rocks. On 

 the whole, these insects of the lias resemble forms of ordinary 

 occurrence and of temperate climes, more nearly, however, ap- 

 proaching those of North America than those of Europe.* 



From the Stonesfield slate and other middle beds of the 

 middle secondary period, the collection of insects described is 

 not numerous, and the specimens, with a single exception (a portion 

 of the wing of a very large neuropterous insect), consist of the 

 elytra of beetles ; the perfect insects in these cases must have 

 varied in length from half an inch to 1^ inch, and some of the 

 larger species were evidently lignivorous in their economy. 



The remains of insects from the Wealden are, on the whole, 

 the most interesting of the series, and the best defined in the 

 collection, and they are considered by Mr. Westwood to afford a 

 tolerably correct average indication of the state of insect life 

 during the wealden period, so far as the series extends. As 

 many as 74 figures of these are given in Mr. Brodie's work, 

 selected from 239 specimens ; and the specimens figured belong to 

 many different orders, among the chief of which are Coleoptera, 

 Orthoptera, JVeuroptera, Hemiptera, and Diptera. 



The minute size of many of these specimens, especially amongst 

 the Diptera and Coleoptera, is worthy of notice, as appearing to 

 indicate a low temperature at the time of their existence, since it 

 is well known that the lower the temperature, the smaller are the 

 insects which inhabit a region ; and although this conclusion is not 

 certain, and some individuals are preserved, which, judging from 

 present insect life, must have been the inhabitants of a warm, if 

 not a tropical climate (e. g. Ricania and some wings), still with 

 these exceptions there seems nothing to warrant the supposition 

 of a climate very different from that of our own country. On the 



* A small collection, consisting chiefly of fragments of minute beetles, is es- 

 pecially alluded to as having been obtained from the supposed Triassic beds of 

 Aust Cliff. The evidence, such as it is, obtained from the examination of these 

 insects, does not warrant the supposition of any difference having obtained in 

 the conditions of their existence. 



VOL. I. D D 



