644 Mr. R. Shelford on the Studies of the Blattidac. 



easy to recognise that species as a typical Ectobiine. But 

 what of the species that exhibit, let us say, two of the 

 above-mentioned features, whilst the third character is 

 typical of the Pseudomopinae ? It is true that the Uctobiinae 

 as a whole have a general facies which enables the expert 

 to recognise them almost at a glance, but it is impossible 

 to define this facies in cut-and-dry phrases. For example, 

 it would be folly to remove " Theganopteryx " malagassa 

 Sauss., from the Uctohiinae, or the two species of Chrasto- 

 hlatta from the Pseudomopinae. Yet in the former species 

 the apical triangle is not sharply marked off from the rest 

 of the wing, and the two latter species have the femora 

 most sparsely armed. Quite apart from this difficulty of 

 expressing in words the Ectobiine facies, there is the 

 difficulty of placing the genera which present neither 

 an Ectobiine nor a Pseudomopine facies ; these baffle even 

 the specialist. Mallotohlatta, Sauss., and Escala, mihi are 

 cases in point,* they present some Ectobiine characters 

 but do not look like Uctohiinae, and to include them in the 

 Ectohiinae renders a diagnosis of the whole subfamily 

 more difficult than ever, and the same happens if they 

 are included in the Pseudomopinae. 



It is perhaps the irony of fate that in this, my last 

 serious contribution to the taxonomy of the Blattidae, 

 I feel compelled to recant some of the opinions expressed 

 in my first essay on the same subject. In that paper 

 (Trans. Ent. Soc. London, 1906) I, with all the rashness 

 of inexperience, rushed in where such authorities as 

 Brunner von Wattenwyl and de Saussure had feared to 

 tread, and declared with no uncertain voice that the 

 simple or bifurcate ulnar vein of the wing was a char- 

 acter of the greatest reliability whereby to separate the 

 Pctohiinae from the Pseudomopinae. The position cannot 

 be held. Reliance on this character involved the removal 

 o{ Jfemithyrsoccra from the Pseudomojnnac to the Ectohiinae, 

 but further knowledge has shown me that its genus is 

 akin to Blattella, in fact the two genera grade into each 

 other. Moreover, when the wings of a cockroach become 

 reduced in size or semi-aborted the first wing-veins to 

 disappear are the branches of the ulnar vein, consequently 

 nearly all the species of Ccratinoptcra, a truly typical 



* It is some comfort to know that de Saussure was evidently as 

 puzzled about the correct systematic position of Mallotohlatta as 1 



