THE CHAIN-SPOTTED GEOMETER. 31 



They often grow to aD enormous size compared with their usual de- 

 velopment. They do not find their food exclusively on the bogs, but 

 when nearly full-grown they Jiave the habit of biting pieces out of the 

 cranberries, which, of course, soon wither and die. They seldom eat 

 an entire berrv, but usually eat out the seeds and then leave it. The 

 cricket has the same habit. Probably all the species of locust, found 

 in the various localities find their way on the bogs, and none live ex- 

 clusively in them, for I found the same species that were common on 

 the bog were also common in the woods and fields everywhere in the 

 vicinity. A cheap and very effective remedy against the depredations 

 of these insects is a flock of turkeys. Dr. Brakeley has between 50 and 

 100, which day by day journey to the bogs and cross and recross them 

 in every direction, coming home each evening with crops distended to 

 their fullest extent. The difference between his bogs and those of his 

 neighbors, in the matter of locusts, is marked; only an occasional one 

 will fly u.p before you on his bogs, while on the other bogs visited by 

 me locusts started up everywhere by the dozen. Both pyrethrum and 

 kerosene kill the locusts when they come into contact with them, but 

 turkeys constitute by far the best and easiest remedy to apply. 



THE CHAIN-SPOTTED GEOMETEE. 



(Zerene catenaria Gn.) 



On some bogs of Cape Cod an insect locally known as the yellow 

 span worm sometimes becomes somewhat injurious. The parent of the 

 larva is known as the " chain-spotted geometer," and is pure white, 

 except for the front of the head and the shoulder tippets, which are 

 yellow. The fore wings have a narrow, zigzag black line on the inner 

 third of the wing, a distinct, black discal dot and a scalloped black line 

 half-way between the discal dot and outer edge. The hind wings have 

 a black discal dot and a single black line, often more or less broken at 

 the outer third of the wing. It expands nearly 2 inches. 



The larva is lh inches or more in length, equally thick throughout, of a 

 bright sulphur-yellow color with paler and black markings. It is readily 

 recognized and easily seen on the bogs; it is found in moderate numbers 

 on the various bushes growing at the edge of the bogs, and appears a 

 general feeder. The uniform testimony is that the young larvae are 

 never found on the bog, but when they attain the length of an inch 

 they sometimes leave their natural food-plants and invade the bog. eat- 

 ing rapidly and doing considerable damage. 



The remedy for this lies in prevention, and is easy: Clear the ditches 

 surrounding your bog, have them at least two feet wide and half lull of 

 water, and cut off the brush for a few feet from the edge of the bog. The 

 remedy is complete. 



