150 MISCELLANEOUS FOREST INSECTS. 



within their host perhaps during the greater part of the year, while 

 the adults are to be found in the host only within a very short period 

 of the year, namely, just before they leave the host. A tree or piece 

 of wood may be found to be badly infested and damaged by Ceram- 

 bycoid larvae, and no adults present to give a clue to the identity of 

 the species. In fact, there may be several species present. The 

 question immediately arises, "Which is the destructive species and 

 what is it ? What are the known habits of the species ? And what 

 relation to the damage done, and to the primary enemy, do the other 

 species bear?" Without knowing the identity of the destructive 

 species one is at sea as to its known habits and the methods which 

 may have been used to combat it. This necessitates the working out 

 of life history and habits in each case. It can thus be seen that much 

 time and labor would be saved if the larvae could be readily identified. 



As indicated above, the making of a table by which the genera of 

 cerambycoid larvae can be recognized is extremely difficult. The 

 first requisite is, of course, the possession of authentically identified 

 specimens of the different genera. To gather together such a col- 

 lection is in itself a stupendous task. Cerambycoid larvae are to be 

 found in abundance, and in many cases in situations which seem to 

 indicate the identity of the species. But right here is where extreme 

 care must be exercised to avoid making serious mistakes. The fact 

 that a certain larva is taken from a piece of wood or bark, and that 

 later a certain adult Cerambycoid is reared from the same host, is 

 by no means proof that the larva and adult are the same species. 

 In fact, adults of two or three species are often reared from the same 

 piece of wood. The most conclusive proof of the identity of a given 

 larva is obtained by rearing it to the adult stage in a vial or other 

 receptacle, where it is kept entirely to itself until the adult stage is 

 reached. In order to do this the larva must be taken from its host 

 only after it has practically completed its growth. If the collector' 

 cuts out a half-grown larva there is practically no chance of rearing 

 it to the adult stage. It can not complete its growth and go through 

 its metamorphoses outside of its natural envirr-nment. However, 

 the building up of a collection of larvae identified by this method is 

 such a slow process that for practical purposes the writer has accepted 

 as authentic, identifications made in other ways. Thus, where sev- 

 eral larvae, exactly similar morphologically, have been found together 

 with pupae and adults, all of which are the same species, he has con- 

 sidered the larvae to be the same species as the adults. 



In all, the writer has studied the larvae of 46 genera of Ceram- 

 bycoidea; 15 in the family Lamiidae, 18 in the family Cerambycidae, 5 

 in the family Lepturidae, 5 in the family Prionidae, and 3 in the family 

 Asemidae. Henshaw lists 175 genera of Cerambycidae for America 

 north of Mexico. Therefore it is readily seen that the present effort 



