224 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



specimens in every possible stage of oviposition, we have been able to 

 ascertain the exact method by which the egg-mass is formed. The pro- 

 cess has never been accurately described by other writers, and the general 

 impression — upon which figures like those of Gerstiicker's^^ are founded — 

 is that the eggs are extruded from between the distended hooks or 

 valves. If we could manage to watch a female from the time the bot- 

 tom of her hole is moistened by the sebific fluid, we should see the 

 valves all brought together, when an egg would pass down the oviduct 

 (Fig. 3jj) along the ventral side, and, guided by a little finger-like style 

 (the giihernaculum ovi, g)^ "pass in between the horny 

 valves (which are admirably constructed, not only for 

 drilling but for holding and conducting the egg to its 

 appropriate place), and issue at their tips amid the 

 mucous fluid already spoken of. Then follows a period 

 of convulsions, during w^hich more raucous material is 

 elaborated, Hntil the whole end of the body is bathed 

 in it, when another egg passes down and is placed in 

 position. These alternate processes continue until the 

 full complement of eggs are in place, the number ranging 

 from 20to 35, but averaging about 28. The mucous mat- 



FlG. 3.— OVIPOSITION ,., ' . -., ,, .,. 



OF KocKY Mountain ter biuds all the corgs m amass, and when the last is laid, 



Locust. (After Eiley.) , , , ° . / ^„. ■, , 



the motherdevotessometimefofilling up the somewhat 

 narrower neck of the burrow^ with a compact and cellulose mass of the 

 same material, which, though light and easily penetrated, is more or less 

 impervious to water, and forms a very excellent protection (Fig. — , d]P 

 When fresh the mass is soft and moist, but it soon acquires a firm con- 

 sistency. 



"'During the operation the female is very intent on her work, and 

 may be gently approached without becoming alarmed, though when sud- 

 denly disturbed she makes great eftbrts to get away, and extricates her 

 abdomen in the course of a few seconds, the time depending on the 

 depth reached." 



The legs are almost always hoisted straight above the back during 

 the process, as shown in the figure (Fig. 1), with the shanks hugging 

 more or less closely the thighs. Sometimes, however, especially when 

 the abdomen is fully buried, the ends of the hind feet may rest firmly on 

 the ground, as has been observed by Mr. Packard in the case of femur- 

 rubrum, 



"The time required for drilling the hole and completing the pod will 

 vary according to the season and the temperature. During the latter 

 part of October or early in November, 1876, when there was frost at 

 night and the insects did not rouse from their chilled inactivity until 9 

 o'clock a. m., the females scarce had time to complete the process during 

 the four or five warmer hours of the day ; but with higiier temperature 

 not more than from two to three hours would be required." 



22 Die Wanderheuschrecke, Berlin, 1876, Taf. II, Fig. 4.' 



