14 BULLETIN NO. 3, DIVISION OF ENTOMOLOGY. 



There is but little grass on the cranberry bogs under cultivation, and it was found 

 that those squares bad suffered most on which there was most grass, while on those 

 squares where the cranberry vines had nearly exterminated the grasses very little or 

 no damage at all had been done. 



No living specimens of the insect that really did the damage could be found, as was 

 to be expected after the lapse of more than six weeks, the worms having been seen 

 on the bog about June 20; but the following traces thereof were discovered: 1, The 

 ground on the damaged squares was literally strewn with excrement, which, though 

 much decomposed at this time, was unmistakably that of a Lepidopterous larva; 2. 

 Numerous heads of a Noctuid larva were found on the ground, most of them in a badly 

 decomposed state, and but a few among them in fair condition. These heads were 

 so abundant that there could not be the least doubt that they belonged to the de- 

 structive larva. The Sarracenias growing in some places in the bog each contained 

 numerous specimens of the decomposed larva?, but in the course of the examination 

 a few fairly well preserved specimens were found ; 3. Of pupae, or rather empty shells, 

 very few could be found, and it appears that the wet ground had prevented the worms 

 from entering the same, and that they mostly perished above ground without trans- 

 forming ; 4. A number of empty Microgaster cocoons, indistinguishable from tbose of 

 JSI. congregatus. 



I will also remark in this connection that I found two specimeus, tbe only ones I 

 saw, of the saw-fly sent by Mr. Van Hise as the originator of the damage. It was 

 feeding on a species of Scjrpus (?) wbicb grows in the irrigation ditches. 



The cultivated bog is flooded with water during winter and spring to a depth of 

 several feet, so that no Lepidopterous larvae can hibernate in it. The uncultivated 

 part is also under water most of the time mentioned, but not so thoroughly as the 

 cultivated portion. Outside of the cranberry lands there is but little graminaceous 

 vegetation in the pine barrens. On the 10th of May the water is drawn off from tbe 

 l)og, an operation which is accomplished in little more tban 24 hours. After this 

 the cranberry A'ines and other vegetation start vigorously, the grasses, one or two 

 species of which grow in thick bunches, being there much fresher than anywhere else 

 in tbe neighborhood. 



From Mr. Rockwood's and Mr. Van Hise's observations there can be no doubt that 

 the larvae first devoured every blade of grass on the squares where the eggs were de" 

 posited and that they afterwards, from mere want of other food, began to attack the 

 cranberry vines. They destroyed only the young vines (i. e., those wbicb should have 

 been bearing this and the next seasons), eating the young, fresh leaves before these 

 had fairly opened. At the time of my visit these young twigs had the appearance of 

 being cut with a knife. Mr. Van Hise further states that he saw the worms appear 

 in great numbers at the edge of the irrigating ditches, a great many of them being in 

 the water and on the rushes growing in the ditches. This observation is no doubt 

 correct, as the worms, after passing through one of the squares, finally congregated 

 -at the edge of the irrigating ditch and tried to get across, and in doing so got at the 

 rushes, which at the time of my visit still bore evidence of their attack. In general 

 the irrigation ditches were evidently an effectual barrier against the progress of the 

 worms, and whether they succeeded, in one or two instances, in crossing the ditches, 

 or whether the damage on the adjoining squares was caused by worms that hatched on 

 the same, could not be ascertained. At any rate their feeding on the rushes in the 

 water was the reason of the confusion in regard to the saw-fly larvae. Mr. Van Hise, 

 being instructed to collect specimens of the cranberry enemy at a time when the real 

 depredators had disappeared, naturally did not find any other worms on the rushes 

 than the saw-fly larvae, which seem to have been very numerous in the beginning of 

 July. 



In regard to other injurious insects observed by me on the cranberry bogs. I would 

 mention that at the time of my visit serious damage was done by various species of 

 locusts (Aerididfp^, by eatiug large holes in the berries. Mr. Van Hise resorts to the 



