folsom: mouth-paets of anukida makitima. 121 



from tlie head of the maxilla, but through an opeuiug iu the constricted 

 region nerve fibres may be traced to the lacinia. 



At this stage (7) the first maxillary palpus (Plate 5, Figure 30, pip.), 

 though still present, is no larger than it was in Stage 5 (Figure 22, pjlp.). 

 In the newly hatched insect no trace of this palpus exists, hence it must 

 have been resorbed. In the adult Orchesella, on the contrary, the 

 palpus is functional and highly developed ; other facts also indicate that 

 An arid a is a degraded form. 



Von Stummer-Traunfels ('91, p. 226, Taf. I. Figuren 6, 7), following 

 TuUberg ('72, Taf. IV. Figur 17), observed a connection between the 

 maxillary palpi and the so-called paraglossae of Collembola, and makes use 

 of this union (p. 22G) as the first of his reasons for recommending an im- 

 proved designation of the mouth-parts, in the following words : " I. Die 

 grosse Unwahrscheiulichkeit, dass der sogenannte Maxillartaster der Col- 

 lerabolen vvirklich zur Maxille gehort, indem diese von jenem vollstandig 

 getrennt ist und derselbe vielmehr in innigem Verbande mit den Para- 

 glossen steht." Hansen ('93, p. 209) uses this conclusion in proving 

 that the " paraglossse " of Collembola and Thysanura are homologous 

 with the first maxillae of Crustacea. Without discrediting his conclu- 

 sion, I have already shown (Folsom, '99) upon anatomical data the 

 trivial nature of the union between palpus and " paraglossae " (super- 

 linguae). I have now proved upon embryological evidence (Plate 3, 

 Figure 22) that the palpus belongs to the maxilla, and have also shown 

 (p. 114) that the chitinous membrane connecting it with the superlingua 

 is simply incidental, and is only that part of the wall of the maxillary 

 pocket which necessarily intervenes between the first maxilla and super- 

 lingua of the same side. 



The fundament in Isotoma designated first maxilla by Packard ('7I, 

 Plate 3, Figure 13) is undoubtedly, from its position in relation to the 

 first pair of legs, second maxilla ; therefore what he regards in the same 

 figure as a mandible must be a first maxilla. Ryder ('86) followed 

 Packard in this matter, but Wheeler ('93, p. 57, Figure 6) shows the 

 fundaments in their proper position. 



Claypole ('98) correctly identifies the first maxillary fundaments in 

 Figures 43, 46, and 47, but does not mention the palpus. 



Uzel ('98) gives a figure of the first maxillary fundaments of Tomo- 

 cerus and remarks (p. 36) : " In jenera Stadium, bei welchem die Um- 

 rollung des Keimstreifs vollendet ist, bemerken wir, dass sich die Anlagen 

 des ersten Maxillenpaares (Taf. VI. Figur 87, mx..^ in zwei Hocker getheilt 

 haben, und zwar in einen ausseren langlichen und in einen inneren 



