April, 1918] Parasites of Leaf- Hoppers 205 



only mouth ])arts. A large mid-intestine beginning just back of 

 the head extends throughout the greater length of the body 

 to near the anal end. The pharynx-esophagus is a very narrow 

 tube, distinguished below the supra-esophagial ganglia. The 

 hind-intestine is contiguous with the mid-intestine, but there 

 is no connection between the two. In Aphelopus melaleucus 

 Dalm., according to Keilin and Thompson, the salivary glands 

 are very long and have a winding course. They were not seen in 

 the specimen studied by the writer. Twelve ventral ganglia 

 are easily distinguishable, the two anterior of which are doubtless 

 thoracic and cephalic. The second is connected with a more or 

 less elongated ganglion located just ventral to the first or sub- 

 esophagial ganglion. The above mentioned authors report 

 finding fourteen ganglia in the ventral nerve chain of Aphelopus 

 nielaleucus Dalm. instead of twelve, which is the ordinary 

 number in other Hymenopterous larvae. Nine pairs of spiracles 

 are present in this stage. 



Third ijistar. — In this stage the larva assumes a more marked 

 curved position, being bent ventrally in the form of a U, the 

 cephalic and caudal ends being approximate, (Fig. 12). The 

 head and anterior third of the body lie buried in the tissues of 

 the host, the rest of the larva protruding externally. It is 

 completely enclosed in the second exuvium, except the head 

 region. The first exuvium lies midway across each side of the 

 body. In some species the ventral portion of the body immedi- 

 ately back of the head is prolonged into a peculiar appendage, 

 which is enclosed by a cone-shaped membrane, the cuticle of 

 the second exuvium. This is turned outwardly and posteriorly 

 and its tip lies just beneath the chitin of the host at the juncture 

 of two metameres, and is often visible externally in the case of 

 light colored nymphs as a dark brown process extending under 

 the cuticula from the point of attachment of the parasite. 

 Often there is no corresponding larval tissue within this and 

 in this case a small opening is noticed at the tip. It may serve 

 to tap the outside air and thus keep a supply under the second 

 exuvium for the enclosed larva. There is no connection between 

 the spiracles of the second exuvium and the larva unless the 

 thoracic pair retain this as they do in the next stages. The 

 mouth parts are similar to those of the preceding stage except 

 that they are larger. In Gonatopiis contortiihis Patton they appear 

 as two oval, fleshy lobes projecting prominently from the head 



