BRANCH ARTHROPODA; CLASS IN SECT A : THE INSECTS i?5 



in Comstock and Kellogg's " Elements of Insect Anat- 

 omy," chap. VII. 



Of how many segments is the abdomen composed ? 

 The first or basal segment is depressed, while the others are 

 more or less compressed. The spiracles are, as in the locust, 

 situated on the lateral aspects of the abdominal segments. 

 What segments bear spir- 

 acles ? The terminal seg- 

 ments of the abdomen 

 differ in the two species. 

 In the female the dorsal 

 part of the Apparently) 

 last segment is longer 

 than the ventral part and 

 is bent down over it form- 

 ing a sort of hood over a 

 space enclosed partly by 

 this hood, partly by a 

 bluntly-pointed projection 

 from the ventral surface, 

 and party by the lateral 

 margins of the segment. 

 In this chamber lies the 



Opening from which the FIG. 43. Wings of monarch butterfly, 

 eggs issue. In the male Anosiaplexippas to show venation ;/ 



costal vein ; sc, sub-costal vein; r, radial 



there are several back- vein; r, cubital vein; a, anal veins. 

 .- i In addition most insects have a vein 



ward - projecting, horny, ^^ the sub costal and ra _ 



thin processes. dial veins called the median vein. 



Make a drawing of the lateral aspect of the whole body. 



Life-history and habits. The tiny, conical, yellowish- 

 green eggs of the monarch butterfly are deposited on the 

 under side of the leaves of milkweeds (Ascleptas} and 

 when examined under the microscope are seen to be very 

 beautiful little objects finely ribbed with longitudinal and 

 transverse striae. The eggs are laid in April and May 

 (depending on the lacitude and season) by females which 



