JOURNAL Jlf\a JBork ^Inj^omologiral HoriFig* \rol. VII. JUNE, 1899. No. 2. NOTE ON THE SECONDARY ABDOMINAL LEGS IN THE MEGALOPYGIDiE. plate ii, figs. 1-3. By Harrison G. Dyar. I have contended that the additional pairs of abdominal legs present in Megalopygidse on abdominal segments 2 and 7 are secondary struc-tures, leading up to the form shown in the Eucleidae. Recently in watching the progression of a larva of M. operciilaris on a smooth glass surface, I observed that the parts of the feet bearing crotchets were not used, but a small disk on the anterior side of each foot was applied to the glass in the same way as the membranous feet of segments 2 and 7. There is no disk on the last segment. Thus the Megalopygidse have two distinct sets of abdominal feet, the normal ones, with crotchets, on segments 3 to 6 and 10 and the secondary membranous ones, function-ing more as sucking disks, on segments 2 to 7. The larvae are adapted to walk both on rough surfaces with the r hooked feet, or on smooth ones with the membanous disks. The structures which I mention have been detected by Burmeister and accurately described. He says that segments 2 and 7 have " un couss n rond aplati, qui res-semble a la plante d'un pied ;" on segments 3 to 6 ** il y a un second coussin plus grand, qui ressemble, a une veritable patte membraneuse porvue d'une plante sineuse et d'une couronne de petits crochets cor-nes;" on segments 10 a normal foot " completement conformee comme les quatres moyennes des six anneaux anterieurs mais sans la petite plante accessoire de celles-ci." I have italicized the important words. Fig. I shows the ventral aspect of the membranous foot of M. opercii-laris on abdominal segments 2 and 7 ; Fig. 2 the foot of segments 3 to 6 with the disk in front and the bent line of crotchets behind; Fig. 3 shows the normally formed foot of segment 10. I wish to emphasize this interpretation of these peculiar abdominal feet, as I believe that it shows very well the origin of the creeping disk of the Eucleidae. Me-
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