14 THIRD ANNUAL REPORT OP 



badly attacked. They also gnaw large holes in the leaves, and when 

 nothing else presents, will feed on the bark of the tender twigs. 



The beetles often make a peculiar creaking noise (a fact not 

 mentioned before of this species) by rubbing the tip of the abdomen 

 up and down against the wing-covers.* 



Let us be thankful, therefore, that there can no longer reasonably 

 be dilference of opinion, or discussion on these questions, which, 

 though of no very great practical importance, were yet of great 

 interest to us all. 



IT IS NOCTUNRAL RATHER THAN DIURNAL, 



Before leaving this little Turk, however, I have some other facts 

 to mention which were first brought to light the present year, and 

 which have a most important practical bearing. The people of the 

 West have been repeatedly told, and with so much assurance that 

 they no doubt have all come to believe it as gospel, that Curculios 

 fly only during the heat of the day, and that it is useless to endeavor 

 to catch them after say 10 o'clock in the morning. What I am about 

 to utter will iio doubt astonish many, but I know whereof I speak. 

 The Curculio is a nocturnal rather than a diurnal insect; is far 

 more active at night than at day, and Hies readily at night into the 

 bargain. If any one doubts this assertion, let him go into his peach 

 or plum orchard at midnight with a lantern and sheet, and he will 

 catch more than he could during the day, and will also find, to his 

 sorrow, that they are then much more nimble and much bolder— 



*A great many different beetles belonging- to widely different families have the power of mak 1 - 

 ins,- a stridulating creaking noise, and though the instrument is found upon different parts of the 

 body in different species, yet it is always made after one plan, namely, a file-like rasp and a 

 scraper. In Darwin's new book (Descent of Man, pp. 366-73) an interesting account of the dif- 

 ferent methods employed will be found. Every entomologist knows how commonly this creaking 

 noise occurs in the Long-horn beetles, and that the rasp is situated on the mesothorax and is 

 rubbed against the prothorax. In the Burying beetles (NECnopnoniD.E) these rasps are situated on 

 the filth abdominal joint, and are scraped by the posterior margin of the elytra. In the Dung- 

 beetles again it is variously situated upon different portions of the body. Dr. Fitch (10th Ann. 

 Rep. p. 12) has noticed the creaking noise made by the Three-lined Leaf-beetle (Lcma trilineata) 

 which is produced by the same motions as those witnessed in our Curculio ; but in this instance, as 

 in all other stridulating Chrysomelidse, the rasp is situated on the dorsal apex of the abdomen 

 known as the pygidium, and is scraped by the wing-covers ; while in the closely allied Curculionida> 

 which have this power the parts are completely reversed in position. Any one who will take the 

 trouble to carefully examine the wing-covers of our Plum Curculio will find on the lower apical 

 edge of each, a horny, slightly raised plate, about a third as long as the whole wing-cover, and 

 transversely and obliquely ribbed by numerous parallel ridges. There is also a longer cord or carina 

 near the sutural edge which may help to intensify the noise. The dorsal apex of the abdomen or 

 pygidium forms a yellowish and roughened plate, with the sides horny and emarginate, so that 

 when the abdomen plays up and down, these horny edges grate or scrape at right angles against 

 the rasp. 



In some instances the stridulation is possessed principally by one sex and serves no doubt as 

 a sexual call ; but with our Curculio as with most other stridulating beetles, both sexes seem to 

 share alike in the power, and it then no doubt serves as a mutual call, or is used under the in- 

 fluence of distress, fear, or even pleasure; for I have always more particularly noticed the noise 

 of an evening when the Curculios were most active and preparing for their active night work. 



