24 INSECTS INJURIOUS TO GARDEN AND ORCHARD CROPS. 



Fifth stage (fig. 4. e).-— The last nymph stage is so distinct from all 

 previous stages that a description is scarcely necessary, as this form is 

 sufficiently shown by the illustration. It is characterized chiefly by the 

 increased growth of the thorax, which is now longer as well as wider at 

 the base, and more particularly by the lengthening of the wing-pads— 

 two changes which produce an increased semblance to the mature bug. 

 The hairiness of the legs and antenme which was so pronounced in the 

 first stage has gradually become less and less evident with each suc- 

 cessive molt until the hairs now. although plentiful, are little more 

 than fine short bristles. Length when first molted. 9 or 10 mm , just 

 twice as long as wide. 



BRIEF DESCRIPTION OE THE ADTLT. 



To complete our knowledge of the different stages of this species the 

 accompanying illustration of the adult is added. Figure 5. a represents 



a female bug. about twice the natural 

 size. It measures a little less than 

 three fourths ot an inch (14tol6 mra )in 

 length, is dirty dark brown above and 

 mottled yellowish beneath. The hau- 

 stellum. seen in the profile of the head 

 and thorax (&), passes when at rest 

 under the body. The terminal seg- 

 ments of the abdomen of the sexes are 

 shown at c and d. the former repre- 

 senting the male, the latter the female. 



THE PERIODS OE THE LIEE CYCLE. 



Fig. 5. — Anasa tristisj a. mature female : i, side 

 view of Lead, showing hanstelToni: c, abdom- 

 inal segments of male: d. same of female; The Carrying of this Species through 

 a. twice natural size: 6, c. d, slightly more a l] ftg sTa geS in the rather ClOSC COn- 



enlarged (original i. . 



finement of small rearing jars gave 

 variable results in the periods. Only two of these, the egg and the first 

 stage of the nymph, were at all constant for the same temperature. 



The egg period was found to vary from eight to thirteen days, this 

 period depending as do other periods on the exposure to heat or cold, 

 dryness, or humidity. The later periods were also influenced perhaps 

 by the food supply. The usual period of the egg is between nine and 

 ten days. 



The first nymph stage requires a period of three days, or a little less; 

 the second was passed in eight and nine days: the third in seven and 

 eight days: the fourth consumed six days for this period: and the fifth 

 stage required eight days. 



As some of the nymphs died in confinement, a number of this lot that 

 had recently hatched were placed. July 3, on a squash plant on the 

 experimental plat connected with this Division on the Department 

 grounds. From these, three adults, the first observed of the season, 



