50 THE EEPOET OF THE No. 36 



In drawing a parallel between Agrilus and Oherea I referred to both form 

 and habit. The form of Brachys, short and broad and somewhat flat, suggests the 

 form of Odontota, a leaf-miner among the Chrysomelians; in habit, since the 

 mature beetle of Agrilus responds to the same food-stimulus as its larva, the eat- 

 ing of hazel and other leaves by the Brachys beetle may mean that the larva mines 

 in such leaves. (Vide Can. Ent, 1887, xix, 159.) 



I have found a great many instances among the Coleoptera where the mature 

 insect seems to be affected in a greater or less degree by the same stimulus as the 

 larva. Perhaps the sight of the larva's food-plant strikes on some happy chord of 

 childish recollection in the mature beetle. 



To the student of animal instinct it is no doubt far more wonderful that an 

 insect in its comparatively short life should at different stages respond to two quite 

 distinct food-stimuli. The syrphus fly {Eristalis tenax), whose larva feeds in 

 liquid manure, is at maturity a honey-sucking haunter of blossoms; in extreme 

 cases, like that of the parasitic oil-beetles, as many as three distinct food-stimuli 

 occur in the life of the individual. 



But in my rambles through the realm of Coleoptera, it is the opposite 

 phenomenon which has struck me most. I mean the number of beetles that are 

 attracted to the food of their larva. I have noticed this especially among the 

 Cerambycidse. In many of them the smell of fermenting sap (where a tree is 

 newly felled or has been injured by the lopping of branches or the mutilation of 

 bark) seems to act as a direct and powerful stimulus in liberating the instinct of 

 reproduction. This is specially noticeable in the Monohammi. In others, again, 

 where perhaps the smell of sap has first drawn the insects to the tree for breed- 

 ing purposes, the sight of the foliage seems to impel the beetles to eat the leaves. 

 This is particularly the case in some genera that approach most nearly to the 

 Chrysomelians. We have a familiar illustration of it in Tetraopes, the Milkweed 

 beetle, whose larva feeds in the stem of the plant while the beetle resorts in large 

 numbers to the leaves, on which it feeds freely as well as breeding. Less con- 

 spicuous examples of the same phenomenon are the Oherea, and still more the 

 Saperda. I have several times captured Saperda vestita feeding on the sheaf of 

 leafy twigs surrounding the basswood stumps, under whose bark the eggs are laid. 

 I have found Saperda moesta eating the leaves of the poplar, where its larva de- 

 velops, and on a single willow I once counted over 200 specimens of Saperda con- 

 color breeding on the leaves and eating the foliage with evident relish. 



These -last few paragraphs have brought me right into the great group of 

 Phytophagous beetles, properly so called; whose larvas, without exception, find sup- 

 port on living vegetable tissue. They comprise three families, the Bruchids which 

 devour seeds, the Cerambycids which attack the woody tissue of trees and shrubs, 

 and the Chrysomelids which feed at all stages on foliage and the more succulent 

 parts of vegetation. 



The Bruchids form only a small group, and the genus Bruchus is the only 

 one of much importance; besides the Pea and Bean Weevils (so called), the only 

 species I have found at all abundant is a minute insect, Bruchus discoideus, some- 

 times plentiful in the blossoms of the white convolvulus or Morning Glory. 



The Cerambycids appear to have been in their origin scavengers, rarely attack- 

 ing sound wood; but the larvae of many of them, before reaching full growth, eat 

 right into solid timber; while others appear to eke out their existence by draining 

 the afflux of sap to the part they have wounded; yet others again have deserted 

 the forest tree that formed their ancestral home and taken up their abode in the 

 fruit trees of our orchards. The larvae develop slowly, and must greatly reduce 



