1923 ENTOMOLOGICAL SOCIETY. 71 



in the side and the eggs introduced. Eggs may sometimes be laid on the glass, 

 but this is rather unusual except with the first batch of eggs, which is usually- 

 infertile. When opportunity was given eggs were freely laid in wheat stems. 

 Temperature perhaps is a more important factor in egg laying than darkness. 

 A cold night will retard egg laying, in fact at a temperature between 45° and 

 50° egg laying ceases. Cool nights also retard feeding, but with the morning 

 sun the beetles become active and egg laying may be accomplished at any hour 

 of the day. Were it not for these daytime ovipositions these observations would 

 never have been recorded, for to approach the breeding cage at night with a 

 light will instantly cause the female to leave the plant and seek seclusion. But 

 in the daytime when the female has started in earnest to lay, the hand lens may 

 be safely used for she will not leave her work or position. The following are 

 some notes made during the act of oviposition: 



Morning of September 15th. The female in breeding cage No. 17 was 

 noticed to be very uneasy walking up and down the plant, and carefully surveying 

 the situation. Having selected a petiole that seemed suitable to her liking the 

 leaf was severed in six minutes. After accomplishing this she secreted herself 

 beneath the leaf. Remaining there only a few minutes she proceeded up the 

 stem again. Bracing herself to the petiole, she began rasping a small hole. 

 She did not feed. Just a minute was required to make the opening. Thirty- 

 six movements of the body were noted in the placing of nine eggs. The time 

 occupied was a little over seven minutes. Contrary to the observations of 

 some authors the eggs are forced up or down the stem by the ovipositor not by 

 the rostrum. The beetle under observation did not change her position, and 

 when the stem was opened it was found there were five eggs above the puncture, 

 two below, and the balance inserted at the puncture. Those at the base and 

 nearest the puncture were more compressed than those higher in the petiole. 

 This is quite frequent, and can be commonly observed in splitting open a small 

 stem. An egg puncture is quite different to a feeding puncture. In the latter 

 case the puncture is larger and smooth, while in the former it is much smaller 

 and the opening is left rough. 



September 19th. Visiting the insectary at 12.45 p.m. a female was observed 

 completing an egg mass of nine eggs on a green petiole, near the base of the 

 plant. An egg puncture had been made, but for some reason did not prove 

 satisfactory, and the mass was laid at the side of the puncture. She was hanging 

 on the stem, head downwards, just below the egg mass, and for nearly one minute 

 continued to probe the eggs with the genital plates until they were adhering 

 to each other and to the plant. They were noticed to be quite "rubbery," 

 indentations made by each thrust of the plates were quite deep, but the egg 

 instantly regained its shape, no mark being left on the shell. Contrary to 

 expectations the beetle did not inspect her completed work, but walked away 

 without turning around. After a tour around the cage she ate nearly half a 

 clover leaf and retired to seclusion. The elasticity of the egg was tested with 

 a needle and found to be very great, fully equal to the strain of being pushed 

 up a hollow petiole. In hundreds of eggs examined which were laid inside the 

 petiole not a single egg was found to be broken. 



October 10th. At 8.24 a.m. a female was observed making a puncture in 

 the under side of a horizontal petiole. She reversed her position, inserting 

 her ovipositor immediately, and in three minutes laid a single egg in the cavity. 

 After withdrawing the ovipositor two minutes were spent in sealing the aperture. 

 In an egg puncture no material is eaten out. A small hole is chiselled through 

 and the opening made by bending back the little flap of tissue like a hinge. If 



