( '^w ) 



XV PreUnmum/ Note on Ike inter pr elation of Insedan and 

 Miirio'iHdan strndvres through a comiHirison with 

 the structures of ('rustacca,. 1^' 0. d. (^RAmi'Ton, 

 Ph.D. 



(MiissMrluiscUs Aj^nculiunil Collci^r, AiuluTst, Mass.) 



IKr.ul N..v.Mnl..'r Itnl. I".>:2(t.| 



In inuUiML' a sorics ol; skuiies of ilu- head iiiul U'nninal 

 structures of tl.c ArthropoclH rclutecl to msects witli a 

 view to cletenimiiuj,^ the hues of developincnt lollcwecl 

 in the evohitiou of the iusectau types o Arthropods, 

 I have been struck witli the fact that uiauy ol the currently 

 ac(.M)t*'»l interpretatious of the struc^tures m insects are 

 HurprisiuMy incorrect. Jn the followu.^ brief note, 1 

 woul.l call attention to the more j^lannj^ inaccuracies, 

 leaviuK the more detailed discussion of the vaiMous phases 

 <,{ the subject to be cU'alt with in a series ol papers m 

 which each of the featuivs can be t.aUen up separately 

 and illustrated by the necessiiry drawings to prove tlie 

 points under discussion. . 



One of the most ^^laring of the niaccurac.es current 

 concerning the interpretation of the structures of ins.H3ts 

 is the unrversally ac-cepted vu>w that the U.be-hke st ic- 

 tures on either side of the liypopharynx o insects (ca, Ih.l 

 miperling.uie or " paraglossae ") represent the liivst maxdlae 

 (uLilhdae) of Crustacea. Thc^e strucUires on eitlier ^^ 

 of the hypoi.harynx are not the homoh)gues,of the ii st 

 maxillae of Crustacea at all, but represent the 'pamgnaths 

 of Crustacea, as any one who will take the troubh. to 

 compare a inn,yily naiad (nymph) vy.th one ol our common 

 Taopods, such as Ascliiis, ca,n readily see or himself. A 

 comparison of the parugnaths of higher ^'^^^^J^ 

 siniila,r structures in the lower forms, such as /J/'"^-. ^ 

 indicate tha.t th<>. paragnaths are merely detached I 1. 

 of the lirst nuixdlae, which have t,a,ken up a position behind 

 (a.n(l slightly between) the mandibles. 



Kolsom is appaivntly responsible for the mistaken view 

 that the pa,ragnaths of insects (/. e. the superhnguae or 

 ' u-aglosL'") represent the ina,xillulae (first maxillae) 

 <.f\^ru^tacea, for his drawing of the embryo of .l..n<a 



TRANS. KNT. SOC LOND. 1*.)'.^0. I'ARTS III, IV, V. (MMl. ^\) 



