8 Royal N. Chapman 



flooded very early in the spring, makes it seem very probable that the 

 beetles migrate in the fall to higher land for the purpose of hibernation. 



The number of beetles found after the period of frost in the fall, gradu- 

 ally decreases until no more are to be found either on the plants or in the 

 debris covering the ground. After severe frosts beetles have been found, 

 both in New York and in Minnesota, which were in a semi-dormant 

 condition. These are always in the crevices of the leaf axils, and when 

 dislodged they fall to the ground, apparently too numb and helpless to 

 escape. 



Large quantities of Scirpus and of the debris covering the ground have 

 been taken to the laboratory and examined with the greatest care, but 

 nothing more than a few fragments of dead beetles has ever been found. 

 Since much of the Scirpus grows in several inches or even a foot of water, 

 it would seem that there is little possibility of the beetles' falling from 

 the plants in the autumn, spending the winter wherever they fell, and in 

 some way surviving the spring floods. 



One cannot help asking what becomes of the beetles that linger late in 

 the fall and drop to the debris under the plants when dislodged. Are 

 these beetles lost in the spring floods, and do only the beetles that migrated 

 earlier in the fall survive the winter? Or do even these late beetles, as 

 seems to be indicated by a cage experiment, revive in the warmth of some 

 later autumn days and migrate to suitable winter quarters? As yet the 

 assumption that the beetles migrate at all is not proved, altho the circum- 

 stantial evidence makes it seem to be a safe assumption. Certain other 

 buprestid beetles hibernate as adults in the pupal cells, but none are 

 known to migrate to winter quarters (Burke, 1920; Knull, 1920 and 1923). 



ECOLOGY 



Food plants 



The questions of geographic and local distribution are bound up in the 

 food-plant relations, for no amount of searching has detected this beetle 

 anywhere except on the flood-plain bulrush, Scirpus fluviatilis. So far 

 as is known, the distribution of Taphrocerus gracilis is more limited than 

 that of Scirpus fluviatilis, which occurs thruout northeastern and central 

 United States. Even isolated patches of the bulrush have their popula- 

 tion of beetles in central New York and southern Minnesota, while none 

 were found in Lake County, Minnesota. 



Blatchley (1910) states that Taphrocerus gracilis occurs on buttonbush 

 (Cephalanthus occidentalis) , but careful searching in various parts of New 

 York has failed to discover it on this shrub. Since the beetles do some- 

 times light on other plants than Scirpus fluviatilis, it is possible that they 

 may be taken occasionally on buttonbush. 



Parasites 



Egg parasites are the most abundant of all the parasites of this beetle. 

 A small braconid has been found to have parasitized as many as seventy 

 per cent of the eggs toward the close of the season. These parasites 

 usually occur two in an egg, but occasionally one is found and four are 

 not infrequent. The life history of this braconid has not been worked 



