philip p. ("alvekt. 95 



Types which have not been found. 



As a result of Prof. Brauer's letter, it is now possible to say that 



of the 171 species described by Burineister, the present locations of 



his types of the following 11 are unknown to me : 



Calopferyx 3. Tifia Aeschna 17. d'Tsnlis- 



Diastntummit 1 vlarntu 19. Amnzili'^ 



3. tricolora 20. pnpnen.ns'" 



4. campaiinhifa'-- Libelhda 26. Carolina 

 Aeschna 1. lunnluta 32. fiilvia. 



IJhelhila 37. fa.tciata. 



As before, the asterisk (*j indicates the new species. 



Appendix on certain African species of Orthetrum. 



As the researches embodied in this paper originated in an attempt 

 to identify certain species of Orthetrum described by the older au- 

 tliors, it seems not inappropriate to bring together here the notes 

 made upon some types of Rambur, Palisot de Beauvois, de Selys 

 and Brauer, and to correlate their species with those described by 

 Burmeister and by myself. It is one thing to determine whether 

 two nominal species are practically identical or not ; it is another to 

 ascertain if t.wo seemingly different forms are really l;ut extremes 

 of a variable .series. I shall here attempt the former only. The 

 latter requires careful study of a large number of individuals, and 

 only those who have examined such a series, as that in the ^[u.seuni 

 f'lir Naturkiinde at Berlin, can appreciate the extreme difficulty of 

 defining the African species of Orthetrum. 



Tentative Key to some African species of Orthetrum. 

 i I. Front wings with three rows of posttriangulnr cells (two rows in one type 

 of chrysoKtigma, see page 8i5). 

 A. Hind wings of both sexes with at least a slight yellowish basal clond ; nieiu- 

 branule blackish, whitish at the extreme base (except in Ahhotti, 

 where it is grayish-white thnmghout). Abdomen vesiculose at 

 base, contracted at 3. at least in the males. Arcnliis at the second 

 antenodal or more remote. 

 Costa sometimes yellowish, but the reticulation otherwise dark biown or 

 black. No pale yellow stripes on the sides of tiie thorax. 



Frons uniformly colored above 1. contractu ill Kambui. 



Frons above with a pale spot, which is suri'ounded by black. 



2. !!$teiiiiiialc Riirm. and race M >(';//(/« Selys. 

 Costa and aiitunodals in the subcostal si)ace, at least, yellow. 

 No pale yellow stripes on the sides of the thorax. 



3. braclliale Beauvois. 



TRANS. AM. KNT. .SOC. XXV. SEPTEMBER, 1898. 



