Complex sentence: It is difficult to distinguish "Hemipepsis" from their "Pepsis" relatives, however, "Pepsis" tend to be a more metallic black with a deep blue striped patterning.
Split into simpler sentences: It is difficult to distinguish "Hemipepsis" from their "Pepsis" relatives. However, "Pepsis" tend to be a more metallic black with a deep blue striped patterning.