THE AMEEICAN ENTOMOLOGIST. 



151 



when iilmost completely curled up. Ami in 

 this geuus — wonderful to relate — the insect rolls 

 itself up iu an upward instead of a downward 

 direction, like a clown turning a back sum- 

 merset, so that the breast becomes the convex 

 side of the curve, and the back the concave side.* 

 Xo such example, so far as we are aware, has 

 hitherto been recorded by authors as found 

 in any Order of Insects; and we may learn 

 from this and other such oases what pains Na- 

 ture has taken, and how many various devices 

 she has adopted, to enable these poor despised 

 little '• bugs," that are considered by many as 

 beneath the notice even of children, to escape 

 the observation of the rajriads of foes that are 

 constantly seeking to devour them. 



For the reasons stated above, and otliers to 

 be enumerated elsewhere, we have referred 

 the Joint-worm Fly, as will be seen at once 

 from the lieading of this Article, to the genus 

 Isosoma, instead of the genus Eurytoma, which 

 consists exclusively of parasitic insects. Thus, 

 as the reader will perceive, the seeming viola- 

 tion of the great law of the llNrrv of Habits, iu 

 the case of the Joint-worm, is shown to be no 

 violation at all, and to have been based upon 

 pure ignorance of the true classification of that 

 very extensive and interesting and important, 

 but too much neglected group — the great ChnT- 



I'raitiial Results. 



" But," it will be perhaps objected by the 



ut ilitarian s, "of what practical benefit is all 



♦ A full notice of this most remarkable aiul anomalous 



Edit 



I this discussion? "Wliat possible odds can it 

 I make to the farmer, for example, whether it is 

 the so-called Joint-worm Fly that produces the 

 I galls on wheat, rye and barley, or whether this 

 ily is in reality a parasite, and the galls are 

 caused by some unknown gall-gnat never yet 

 seen by mortal entomologist ? What odds again 

 is it to the farmer, whether the same fly pro- 

 duces the knotty galls on wheat, rye and barley, 

 or whether there is a distinct species infesting 

 each of these three plants, and even, as Dr. 

 Fitch maintains, two distinct species producing 

 galls upon barley straws? Lastly, what odds 

 is it to the plain practical farmer, whether or 

 not this fine law of the Unity of Habits, 

 about which you have been making such a 

 pother, has any real existence in nature?" 



Men and brethren! it makes all the odds iu 

 the world! If the Joint-worm galls are pro- 

 duced by a gall-gnat, that gall-gnat must neces- 

 sarily come out long before the autumn; for 

 otherwise— so many thousands of these galls as 

 have been handled by entomologists in the 

 autumn — somebody or other would have cer- 

 tainly bred the supposed gall-making gall-gnat 

 therefrom, or at all events found some traces of 

 it. I'pon this hypothesis, therefore, namely, 

 that Joint-worm galls are made by a (iall-gnat, 

 it would be utterly useless to burn up and 

 destroy the infested straw in the autumn or 

 subsequently; for tlie culprit gall-gnat will 

 have left it long ago in the summer. Nay, it 

 will even be a positive injury to do this; for 

 the straw is then swarming with the so-called 

 Joint-worm Flies in the larva state, which, on 

 the hypothesis of the galls being caused by some 

 unknown Gall-gnat, must necessarily be para- 

 sitic upon that Gall-gnat and therefore be our 

 friends iiistead of our foes. If, on the other 

 hand, the joint-worm galls are really caused by 

 the .Joint-worm Fly— as we have shown above- 

 then it must 1)0 highly beneticial to burn up the 

 infested straw in the autumn or subsequently; 

 for almost all the .Toiiit-worins lie in the straw 

 until the following summer, and of P(nirso, if 

 you burn the straw, you bnni llie culiirir .loiiil- 

 worras at the same time. 



Again: If the very same Ily that causes- 

 Joint-worm galls upon Wheat can also cause 

 similar galls, as we incline to believe, npon 

 Barley and upon Rye, then the farmer cannot 

 escape from the damage inflicted upon him 

 by this little pest, by ceasing to grow Wheat and 

 seeding down his fields to Barley or Rye. If, 

 on the other hand, the converse proposition, 

 which is that maintained by Dr. Fitch, be the 

 true one, then the veniedy jn-l now indicated, 



