1903] MORRILL: —TINGITIDS OF THE GENUS CORYTHUCA 1 33 



bear a much greater resemblance to certain forms of fungi, notably the genus 

 PJwma, and to certain homopterous galls than they do to eggs of any sort." Uhler, 

 to whom were referred the specimens of the Hawthorn Tingis in his note deter- 

 mining the species said: "Your specimens of Tingis belong to the genus 

 Coryt/incd, and seem to be a new phytophagic form of Corythuca arciiata Say. It 

 will hardly do to make a new species out of this insect, as it is one of the several 

 forms which fit into Say's species. It comes near to the race belonging to the 

 /iiglans nigra.'''' 



Better material than that which I have thus far examined would probably show 

 some differences in the nymphs of the oak- and hawthorn-inhabiting Tingis but 

 from a comparison of the eggs alone it is evident that the two forms should not be 

 considered identical or even local varieties. I suggest therefore that the subspeci- 

 fic name Corythuca arciiata crataegi be used in association with the common name 

 Hawthorn Tingis, while Oak Tingis be exclusively used for the common name of 

 Corythuca arcuata. Say in his description not having mentioned the food plant, it 

 will be necessary thus to designate a variety as the type of the species, and the 

 oak infesting variety seems to be the most commonly accepted type. 



The Buttonwood Tingis, Corythuca ciliata Say. 



While to the naked eye or wuth a hand lens the young stages of C. arcuata and 

 C. ciliata are almost inseparable, with a compound microscope, using an objective 

 not lower than one half inch, the two species can be readily distinguished. The 

 most striking characters of each instar of C. ciliata by which it can be distin- 

 guished from C. arcuata are here given : — 



First t>tstar : The spines corresponding to types no. i and no. 2 are not trumpet shaped 

 but are rounded and much larger at the tip than in C. arcuata. Spines corresponding to 

 type no. 2 are especially prominent on the antennae. 



Second instar: Most of the spines which correspond in position to type no. i in 

 C. arcuata are now pointed at the tips; a few have not completely changed from their 

 form in the first instar. The antennae bear prominent spines as before. 



Third, fourtJi. and fiftti instars : These stages are best distinguished from the correspond- 

 ing stages of C. arcuata by the presence of spines corresponding to type no. i but with the 

 form described in the first instar. The spines on the antennae are less prominent than in 

 the first two instars. 



This species was found to be extremely abundant at Amherst, Mass., in Sep- 

 tember, 1902, on the leaves of a buttonwood or sycamore tree {Platatuis occidcutalis) 

 growing near the college grounds. INIany adults were found under the bark as late 

 as the first of June, 1903, but none were found on the leaves. Unfortunately no 

 eggs were collected in the autumn with the other stages, and in the spring none were 

 found in time to allow notes to be made on them for this paper. 



