202 



Hessian Fly. 



Vol. V. 



injured ; but in order to avoid the introduction of strag- 

 gling insects of the kind from adjacent fields, it is re- 

 quisite that a whole neighbourhood should persevere 

 in this precaution for two or more years in succession. 

 This result was obtained, in part, in the course of trials 

 made by Mr Kirk, of Bucks County, Pa., with some 

 seed-wheat from the Mediterranean, in and since the 

 year 1837. His first crop was free from the fly, but it 

 was gradually introduced from adjacent fields; and in 

 the present year the mischief has been considerable. 

 As Miss Morris states that the fly has never made its 

 appearance in Susquehanna and Bradford Counties, 

 seed-wheat, free from the fly, might be obtained from 

 these, and probably from other, localities. 



"The Committee recommend that the conclusions of 

 Miss Morris ' may be subjected to the only eflicient test 

 — repeated observations and effective trials of the pre- 

 caution she advises.' " 



Believing the above to be an observation 

 of very considerable importance, and sincere- 

 ly hoping that repeated trials and examina- 

 tions may confirm its correctness, we have 

 prepared the present notice for the Cabinet, 

 in order to bring it before the agricultural 

 community. 



Miss Morris's observations and inferences 

 agree very well with what we know of the 

 habits of many insects. Thus they are, as a 

 general rule, not produced till their food is 

 ready for them ; while their eggs appear to 

 approach the seeds of plants in the power 

 of enduring long delay and some violence, 

 before they lose their vitality and faculty of 

 development. The eggs of silk-worms are 

 kept for various periodi;, and still retain the 

 susceptibility of being hatched. How long 

 tills power, in some insects, may be capable 

 of enduring, has not been ascertained ; but 

 the presumption arising from their analogy 

 to seeds leaves it by no means certain, (until 

 observations are made,) that the period may 

 not be one of magnitude. The lower ani- 

 mals are said by naturalists to approach, in 

 constitution, much more nearly to vegetables 

 than to the more complex beings of their own 

 class ; and this is acknowledged to be strik- 

 ingly exemplified in the instance we have 

 been reciting. Something analogous may be 

 perceived in the instance of the common 

 fowl ; in which species, the eggs first laid 

 are allowed to remain till enough are accu- 

 mulated for the parent to commence sitting, 

 and without in any way injuring the product. 



That highly and justly distinguished Ame- 

 rican naturalist, the late Thomas Say, has 

 left us an entomological description of the 

 Hessian Fly, in the first volume of the Jour- 

 nal of the Philadelphia Academy of Natural 

 Sciences. He appears never to have identi- 

 fied the insect in an earlier portion of its life 

 than the flax-seed state. Thus, he describes 

 the larva, first state or " maggot" of the ani- 

 mal, as resembling the pupa or second state, 

 except in the dark, reddish-brown colour of 

 the latter ; and alleges that, " when taken 

 from the culm, it is almost inert, exhibiting 

 very little motion to the eye." This was in 

 1817 ; and as that eminent writer was prin- 



cipally occupied in the task, then new, of 

 describing and classifying American insects 

 in their perfect forms, it is entirely credible 

 that he might have erred in relation to their 

 earlier stages ; nor is it wonderful that, in 

 2;3 years, further discoveries should be made, 

 and his account corrrected. What Mr. Say 

 calls the larva, will, if Miss Morris be cor- 

 rect, be considered the early period of the 

 pupa. 



The discovery of Miss Morris, then, ap- 

 pears principally to resolve itself into the 

 fact of the e^g being deposited in the seed ; 

 and into the history of the pale, green worm 

 or larva, as the primary stage of the animal's 

 existence. Tiie account of its periodical 

 change given by Mr. Say is confessedly con- 

 jectural ; and insufficiently explains the pre- 

 servation of tiie species tlirough the winter. 

 His words are, " The history of tlie changes 

 of this insect is probably briefly this." He 

 then proceeds to describe the parent insect 

 in depositing its eggs within tiie sheath of 

 the leaves, near the root of the plant, the 

 fixed mode of life of the flaxseed substance, 

 together with the indentations produced in 

 the straw, the distortion of the flaxseed 

 worm when crowded, and the death of the 

 plant. He then adds the foliov/ing notice ; 

 which ends the recital. " The perfect fly 

 appears early in June, lives but a short 

 time, deposits its eggs, and dies — the insects 

 from these eggs complete the history by pre- 

 paring for the winter brood." The words 

 would seem to imply that there are two 

 broods of these flies ; one for summer and 

 one for winter. If " preparing for the win- 

 ter brood," means laying the eggs which are 

 to produce them, why are not the flies seen 

 in the end of October ; before which time 

 the sheaths of the leaves and the straw itself 

 of the winter wheat do not exist, and at which 

 period no fly of any description is to be met 

 with in the fields ? If, on the other hand, 

 " the insects from the eggs laid in June," are 

 themselves " the winter brood," they are to 

 be found in the stubble after harvest; and 

 cannot possibly be the same individuals that 

 are found next spring in the damaged stalks 

 of the new crop. 



According to the facts believed to be ascer- 

 tained by Miss Morris, the difficulty at once 

 disappears. The fly lives only ten days; 

 during which time it deposits its eggs. The 

 eggs remain unaltered till the wheat sprouts; 

 and the young worm is then below the Sur- 

 face of the earth, in a substance which is not 

 frozen, and which supplies him with food. 



The residence of the worm, as described 

 by Miss Morris, within the hollow of the 

 straw, is precisely like that of certain other 

 insects. The animal that destroys the more 

 luxuriant shoots of the parsley-leaved elder, 



